System and method for evaluating defects in a material

ABSTRACT

The present disclosure provides a system and method for real-time visualization of a material during ultrasonic non-destructive testing. The system includes a graphical user interface (GUI) capable of showing a three-dimensional (3-D) image of a composite laminate constructed of a series of two-dimensional (2-D) cross sections. The GUI is capable of displaying the 3-D image as each additional 2-D cross section is scanned by an ultrasonic testing apparatus in real time or near real time, including probable defect regions that contain a flaw such as a hole, crack, wrinkle, or foreign object within the composite. Furthermore, in one embodiment, the system includes an artificial intelligence capable of highlighting defect areas within the 3-D image in real time or near real time and providing data regarding each defect area, such as the depth, size, and/or type of each defect.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application relates to and claims priority from the following U.S.Patent Applications. This application is a continuation-in-part of U.S.patent application Ser. No. 17/184,061, filed Feb. 24, 2021, which is acontinuation-in-part of U.S. patent application Ser. No. 17/172,723,filed Feb. 10, 2021, which is a continuation-in-part of U.S. patentapplication Ser. No. 17/149, 320, filed Jan. 14, 2021, which is acontinuation-in-part of U.S. patent application Ser. No. 17/148,205,filed Jan. 13, 2021, which is a continuation-in-part of U.S. patentapplication Ser. No. 17/123,970, filed Dec. 16, 2020, which is acontinuation-in-part of U.S. patent application Ser. No. 17/122,410,filed Dec. 15, 2020, which is a continuation-in-part of U.S. patentapplication Ser. No. 17/108,472, filed Dec. 1, 2020, which is acontinuation-in-part of U.S. patent application Ser. No. 17/091,774,filed Nov. 6, 2020, which claims priority from U.S. Provisional PatentApplication No. 63/001,608, filed Mar. 30, 2020. Each of theabove-mentioned applications is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The disclosure relates to the field of non-destructive testing andnon-destructive inspection and more specifically to a systems andmethods for visualizing defects within a structure duringnon-destructive testing.

2. Description of Related Art

Non-destructive Testing (NDT), also known as Non-destructive Evaluation(NDE) or Non-destructive Inspection (NDI), has achieved popularity intesting materials and parts of larger machines as the methods do notgenerally render the material or part unfit for its intended purpose.Traditional methods of NDT include ultrasonic and thermographictechniques, as well as ones based on the use of eddy currents, radiation(including gamma, X-ray, and microwave), magnetic particles, dyepenetrants, and more. NDT has traditionally been used to detect surfaceflaws of a material, detect delamination between different layers of amaterial, or indicate the presence of other defects within the material.

Prior art patent documents include the following:

U.S. Pat. No. 9,207,639 for Transforming A-scan data samples into athree-dimensional space for facilitating visualization of flaws byinventor Ratering, filed Jan. 24, 2013 and issued Dec. 8, 2015, isdirected to visualizing one-dimensional A-scan data samples in athree-dimensional space. Each of the data samples represents ultrasonicsignals received from a test material. The data samples are transformedinto the three-dimensional space as a geometric shape corresponding to arelative amount of ultrasonic energy reflected back from the testmaterial. The data samples as transformed into the three-dimensionalspace with the geometric shapes rendered therein can be displayed.

U.S. Pat. No. 8,265,886 for Non-destructive testing, in particular forpipes during manufacture or in the finished state by inventors Bisiauxet al., filed Jun. 25, 2007 and issued Sep. 11, 2012, is directed to Anon-destructive testing device for pipes is provided. The deviceextracts information on defects from signals captured by ultrasoundreceivers following the selective excitation of ultrasound transmittersaccording to a selected time rule. The receivers form an arrangementwith a selected geometry, coupled in an ultrasound fashion, withrelative rotation/translation movement, with the pipe. The deviceincludes a converter that selectively isolates a digital representationof echoes in designated time windows, as a function of the movement, andby extracting an image of defects, a filter which determines presumeddefect zones and properties of these, a combiner to prepare workingdigital inputs from an extract of images of a defect zone, a neuralcircuit receiving the working inputs, a digital decision and alarm stageworking on the basis of the output of the neural circuit, and a sortingand marking robot.

U.S. Pat. No. 9,121,817 for Ultrasonic testing device having anadjustable water column by inventors Roach et al., filed Jul. 9, 2012and issued Sep. 1, 2015, is directed to an ultrasonic testing devicehaving a variable fluid column height is disclosed. An operator is ableto adjust the fluid column height in real time during an inspection toto produce optimum ultrasonic focus and separate extraneous, unwanted UTsignals from those stemming from the area of interest.

U.S. Pat. No. 10,302,600 for Inspection devices and related systems andmethods by inventors Palmer et al., filed Jan. 19, 2016 and issued May28, 2019, is directed to inspection devices include a nozzle portionhaving at least one opening and a transducer disposed in a rear chamberof the housing. The housing has at least one fluid channel defined inthe housing and extending along at least a portion of the rear chamber.The at least one fluid channel is configured to supply a fluid into aforward chamber of the housing proximate the transducer. Related methodsinclude operating an inspection device.

U.S. Pat. No. 4,215,583 for Apparatus and method for bondtesting byultrasonic complex impedance plane analysis by inventors Botsco et al.,filed Nov. 14, 1978 and issued Aug. 5, 1980, is directed to anon-destructive bond testing apparatus utilizes impedance variationrepresented by both the phase and amplitude of the signal vectorresponse of a sonic energy generating and receiving probe, which isapplied to a laminar, honeycomb or fiber composite structure under test.Typical bonding methods for which this bondtester and method areapplicable include adhesive bonding, diffusion bonding, brazing,resistance and impact/friction bonding. A cathode ray tube displays thetip of the vector (as a bright dot) which represents the impedancecharacteristic affected by the structure under test. A null circuitdeletes the response of a non-flawed (or normal) portion of thestructure under test so that a flawed (or abnormal) portion of thestructure produces an impedance variation from the null point, thevariation being represented on a polar coordinate display by theamplitude and angular position of the vector tip, thereby providingdiagnostic information regarding the location and type of the bondlinecondition being detected. Bondline conditions/flaws detectable include,disbonds, adhesive thickness, adhesive porosity, degree of adhesivecure, adhesive (cohesive) strength and forms of in-service adhesive orbondline degradation.

U.S. Pat. No. 4,184,373 for Apparatus for evaluating a bond by inventorsEvans et al., filed May 24, 1978 and issued Jan. 22, 1980, is directedto a means and method for evaluating a bond between first and secondstructures bonded together by an intermediate layer of adhesive. Meansare provided for transmitting a pulse of ultrasonic wave energy into thebonded structures whereby a first reflected pulse may be reflected froma first surface of the first structure, a second reflected pulsereflected from the layer of adhesive, and a third pulse possiblyreflected from the surface of the second structure adjacent the adhesivelayer. Circuit means are provided for sensing the first, second, andthird reflected pulses and for providing an indication of the quality ofthe bond by comparing the amplitudes of the reflected pulses anddetermining if the ratios lie within predetermined ranges.

U.S. Pat. No. 8,347,723 for Sonic resonator system for testing theadhesive bond strength of composite materials by inventors Questo etal., filed May 21, 2010 and published Jan. 8, 2013, is directed to asonic resonator system for use in testing the adhesive bond strength ofcomposite materials. Also disclosed herein are a method of calibratingthe sonic resonator system to work with a particular composite bondjoint, and a method of non-destructive testing the “pass-fail” of thebonded composite bond strength, based on a required bond strength.

US Patent Publication No. 2019/0293610 for Detection of kiss bondswithin composite components by inventors Campbell et al., filed Mar. 22,2019 and issued Sep. 26, 2019, is directed to systems and methods fordetecting a kiss bond in a composite component are provided. Usingreflected ultrasound data representative of reflected ultrasound energyfrom the composite component, a first threshold amplitude value between2% and 5% higher than a predetermined baseline noise amplitude value ofexpected material noise in the reflected ultrasound energy from thecomposite component, and a second threshold amplitude value higher thanthe first threshold amplitude value, one or more occurrences of anamplitude of the reflected ultrasound energy exceeding the thresholdamplitude value and less than the second threshold amplitude value areidentified. The kiss bond is detected in the composite component basedon the identified one or more occurrences of the amplitude of thereflected ultrasound energy.

U.S. Pat. No. 7,574,915 for Simplified impedance plane bondtestinginspection by inventors Kollgaard et al., filed Dec. 28, 2006 and issuedAug. 18, 2009, is directed to an NDI system includes an ultrasonictransducer and an electronic device having an indicator, such as a lightsource. The electronic device energizes the transducer, receivessinusoidal signals from the transducer, determines impedance-planecoordinates corresponding to quadrature-phase separated components ofthe sinusoidal signals, and automatically activates the indicator ifimpedance-plane coordinates exceed a preset threshold. The system may beused in methods of inspecting layered structures such as compositeaircraft components and repair patches applied to such structures.

U.S. Pat. No. 8,234,924 for Apparatus and method for damage location andidentification in structures by inventors Saxena et al., filed Jul. 16,2009 and issued Aug. 7, 2012, is directed to an apparatus and method fortesting composite structures in which ultrasonic waves are used todetect disbonds in the structures are described. The apparatus comprisesa flexible structure carrying acousto-optical transducers such as fiberBragg gratings. During use, the apparatus is mechanically andconformally coupled to the structure under test.

U.S. Pat. No. 7,017,422 for Bond testing system, method, and apparatusby inventors Heyman et al., filed Apr. 2, 2004 and issued Mar. 28, 2006,is directed to a bond strength tester and method for determining certainbond strength parameters of a bonded component, including a phaselocker,a transducer, a loading device that is capable of applying stress-loadsto the bond, a controller for controlling the loading device, a datarecording device to acquire data, and a computer device to analyze datacalculating certain bond strength parameters.

US Patent Publication No. 2014/0216158 for Air coupled ultrasoniccontactless method for non-destructive determination of defects inlaminated structure by inventors Martin et al., filed Aug. 9, 2012 andpublished Aug. 7, 2014, is directed to an air coupled ultrasoniccontactless method and an installation for non-destructive determinationof defects in laminated structures with a width (W) and a multiplicityof n lamellas with intermediate N-1 bonding plants (B), whereas at leastone transmitter (T) in a fixed transmitter distance (WTS) radiatesultrasound beams at multiple positions and at least one receiver (R) ina sensor distance (W SR) is receiving re-radiated ultrasound beams atmultiple positions relative to the laminated structure (S). The methodimages the position and geometry of for example lamination defects andallows for inspection of laminated structure (S) of arbitrary height (H)and length (L), and an individual assessment of specific bonding planes(e.g. B1, B2, B3), as well in situations with constrained access to thefaces of the sample parallel to the bonding planes.

U.S. Pat. No. 9,360,418 for Nondestructive inspection using hypersoundby inventor Georgeson, filed Jul. 17, 2014 and issued Jun. 7, 2016, isdirected to a method and apparatus for inspecting an object. Theapparatus comprises a wave generator and a detection system. The wavegenerator is positioned away from an object. The wave generator emits anultrasonic wave in a direction towards a location on the object suchthat the ultrasonic wave encounters a portion of the object. Thedetection system is positioned at a same side of the object as the wavegenerator. The detection system detects a feature response of a featurewithin the portion of the object to the ultrasonic wave encountering theportion of the object.

US Patent Publication No. 2020/0230899 for In-situ monitoring ofthermoformable composites by inventor Tyson, filed Feb. 1, 2020 andpublished Jul. 23, 2020, is directed to a method and system fordetermining the quality and configuration of a structure that isconstructed from a thermoformable material, such as a thermoplastic orthermoset material, and in particular thermoplastic composite tapes,where heat is applied to cure the thermoformable material. The qualityof the build is monitored during the construction of the structure bydetermining the differential heat flux in the material as it cools fromits elevated temperature. The system and method also may determine thelocation of defects in a structure being constructed so that remedialmeasures may be taken or production operations halted to address thedefect. A transient thermal effect is applied to the structure beingmonitored, such as the thermoformable material being applied, which maybe implemented from the applied heating of the thermoformableconstruction application process or additional heating.

U.S. Pat. No. 9,494,562 for Method and apparatus for defect detection incomposite structures by inventors Lin et al., filed May 27, 2011 andissued Nov. 15, 2016, is directed to methods and apparatus fornon-destructive testing of a composite structure utilizing sonic orultrasonic waves. In response to a wideband chirp wave sonic excitationsignal transmitted from a probe to the composite structure, a probesignal received is correlated with a library of predetermined probesignals and a graphical representation of defects detected is generated.The graphical representation provides detailed information on defecttype, defect location and defect shape. Also contemplated is a probe fornon-destructive testing of a composite structure comprising three ormore transducers wherein each transducer is separately configurable as atransmitter or as a receiver; and a controller coupled to each oftransducer for providing signals thereto and receiving signalstherefrom, wherein the signals provided thereto include signals forconfiguring each transducer as either a transmitter or a receiver, andsignals for providing an excitation signal from each transducer which isconfigured as a transmitter.

U.S. Pat. No. 10,444,195 for Detection of near surface inconsistenciesin structures by inventor Bingham, filed May 5, 2016 and issued Oct. 15,2019, is directed to a method of detecting near surface inconsistenciesin a structure is presented. A pulsed laser beam is directed towards thestructure. Wide-band ultrasonic signals are formed in the structure whenradiation of the pulsed laser beam is absorbed by the structure. Thewide-band ultrasonic signals are detected to form data. The data isprocessed to identify a frequency associated with the near surfaceinconsistency.

US Patent Publication No. 2019/0187107 for Methods for ultrasonicnon-destructive testing using analytical reverse time migration byinventors Asadollahi et al., filed Dec. 17, 2018 and published Jun. 20,2019, is directed to systems and methods for nondestructive testingusing ultrasound transducers, such as dry point contact (“DPC”)transducers or other transducers that emit horizontal shear waves, aredescribed. An analytical reverse time migration (“RTM”) technique isimplemented to generate images from data acquired using the ultrasoundtransducers.

US Patent Publication No. 2018/0120268 for Wrinkle Characterization andPerformance Prediction for Composite Structures by inventors Georgesonet al., filed Oct. 31, 2016 and published May 3, 2018, is directed tomethods that provide wrinkle characterization and performance predictionfor wrinkled composite structures using automated structural analysis.In accordance with some embodiments, the method combines the use ofB-scan ultrasound data, automated optical measurement of wrinkles andgeometry of cross-sections, and finite element analysis of wrinkledcomposite structure to provide the ability to assess the actualsignificance of a detected wrinkle relative to the intended performanceof the structure. The disclosed method uses an ultrasonic inspectionsystem that has been calibrated by correlating ultrasonic B-scan dataacquired from reference standards with measurements of optical crosssections (e.g., micrographs) of those reference standards.

U.S. Pat. No. 10,605,781 for Methods for measuring out-of-plane wrinklesin composite laminates by inventors Grewel et al., filed Mar. 9, 2018and issued Mar. 31, 2020, is directed to methods for measuringout-of-plane wrinkles in composite laminates are described. An examplemethod includes scanning a first side of a composite laminate with anultrasonic transducer. The method further includes locating anout-of-plane wrinkle of the composite laminate on a B-scan ultrasoundimage generated in response to the scanning of the first side of thecomposite laminate. The method further includes associating a firstmarker with the B-scan ultrasound image, the first marker determinedbased on a location of a crest of the out-of-plane wrinkle on the B-scanultrasound image. The method further includes associating a secondmarker with the B-scan ultrasound image, the second marker determinedbased on a location of a trough focal point of the out-of-plane wrinkleon the B-scan ultrasound image. The method further includes determiningan amplitude of the out-of-plane wrinkle based on a distance between thefirst marker and the second marker.

U.S. Pat. No. 10,161,910 for Methods of non-destructive testing andultrasonic inspection of composite materials by inventors Dehghan-Niriet al., filed Jan. 11, 2016 and issued Dec. 25, 2018, is directed to amethod of non-destructive testing includes locating an ultrasonictransducer with respect to a component having a visually-inaccessiblestructure to collect B-scan data from at least one B-scan of thecomponent and to collect C-scan data from at least one C-scan of thecomponent. The method also includes filtering the B-scan data and theC-scan data to remove random noise and coherent noise based onpredetermined geometric information about the visually-inaccessiblestructure to obtain filtered data. The method further includesperforming linear signal processing and nonlinear signal processing todetermine a damage index for a plurality of voxels representing thevisually-inaccessible structure from the filtered B-scan data and thefiltered C-scan data to generate a V-scan image. A method ofnon-destructive testing of a wind turbine blade and an ultrasound systemare also disclosed.

U.S. Pat. No. 7,895,895 for Method and apparatus for quantifyingporosity in a component by inventors Kollgaard et al., filed Jul. 23,2007 and issued Mar. 1, 2011, is directed to a computer implementedmethod, or hardware filtration apparatus, and computer usable programcode for measuring porosity in materials. An ultrasonic signal isemitted from a transmitting transducer in an ultrasonic measurementsystem into a material. A response signal is received at a receivingtransducer in the ultrasonic measurement system from the material. Theresponse signal is filtered to pass only frequencies in the responsesignal within a selected frequency range to form a filtered responsesignal. A porosity level of the material is identified using thefiltered response signal.

U.S. Pat. No. 8,522,615 for Simplified direct-reading porositymeasurement apparatus and method by inventors Brady et al., filed Nov.30, 2010 and issued Sep. 3, 2013, is directed to an apparatus formeasuring porosity of a structure includes an ultrasonic transducerdevice configured to be pressed against a structure, the ultrasonictransducer device being further configured to emit ultrasonic pulsesinto the structure and detect echo profiles; and an electronic deviceincluding: a manager having an interface gate, a back-surface sensinggate and a back surface analysis gate; a pulse generator interfacingwith the manager and the ultrasonic transducer device; a dataacquisition device interfacing with the ultrasonic transducer device andthe manager; and a display having a porosity indicator interfacing withthe manager.

U.S. Pat. No. 7,010,980 for Method of determining the porosity of aworkpiece by inventor Meier, filed Jun. 28, 2004 and issued Mar. 14,2006, is directed to the porosity of a workpiece, in particular aworkpiece made of a fiber composite material is determined. Anultrasonic signal is injected into the workpiece and an ultrasonic echosignal is received from the workpiece. The variation of the amplitude ofthe ultrasonic echo signal with respect to the depth is used as ameasure of the porosity of the workpiece material at the respectivedepth.

U.S. Pat. No. 6,959,602 for Ultrasonic detection of porous mediumcharacteristics by inventors Peterson et al., filed Mar. 12, 2003 andissued Nov. 1, 2005, is directed to plate waves are used to determinethe presence of defects within a porous medium, such as a membrane. Anacoustic wave can be propagated through a porous medium to create aplate wave within the medium. The plate wave creates fast compressionwaves and slow compression waves within the medium that relate to thematerial and structural properties of the medium. The fast compressionwave provides information about the total porosity of a medium. Whilethe slow compression wave provides information about the presence ofdefects in the medium or the types of materials that form the medium.

U.S. Pat. No. 9,297,789 for Differential ultrasonic waveguide curemonitoring probe by inventors Djordjevic et al., filed Sep. 20, 2012 andissued Mar. 29, 2016, is directed to a new methodology, testing systemdesigns and concept to enable in situ real time monitoring of the cureprocess. Apparatus, system, and method for the non-destructive, in situmonitoring of the time dependent curing of advanced materials using oneor more differential ultrasonic waveguide cure monitoring probes. Adifferential ultrasonic waveguide cure monitoring probe in directcontact with the material to be cured and providing in situ monitoringof the cure process to enable assessment of the degree of cure or curelevel in a non-cure related signal variances (e.g., temperature)independent calibrated response manner. A differential ultrasonicwaveguide cure monitoring probe including a transducer coupled to awaveguide and incorporating correction and calibration methodology toaccurately and reproducibly monitor the cure process and enableassessment of cure level via ultrasonic reflection measurements. Theamplitude of the corrected interface response signal reflected from theprobe-resin interface indicating changes in the modulus of the materialduring the cure.

U.S. Pat. No. 6,945,111 for System and method for identifyingincompletely cured adhesive by inventor Georgeson, filed Sep. 28, 2004and issued Sep. 20, 2005, is directed to a system for inspectingadhesive in a composite structure, such as for soft or improperly curedregions, includes a transducer and a processing element. The transducercan transmit a signal, such as an ultrasonic signal, into the adhesivesuch that at least a portion of the ultrasonic signal can propagatethrough the adhesive, reflect off of an interface between the adhesiveand another material, and propagate back through the adhesive. Uponexiting the adhesive, then, the transducer can receive a reflectedportion of the ultrasonic signal. Thereafter, the processing element canidentify a defect, such as soft or improperly cured regions, in theadhesive upon a relationship of an amplitude of the reflected portion ofthe reflected ultrasonic signal to a predefined threshold.

U.S. Pat. No. 10,697,941 for Method and system of non-destructivetesting for composites by inventors Jack et al., filed Mar. 20, 2013 andissued Jun. 30, 2020, is directed to method and system are disclosed forcharacterizing and quantifying composite laminate structures. The methodand system take a composite laminate of unknown ply stack compositionand sequence and determine various information about the individualplies, such as ply stack, orientation, microstructure, and type. Themethod and system can distinguish between weave types that may exhibitsimilar planar stiffness behaviors, but would produce different failuremechanisms. Individual ply information may then be used to derive thelaminate bulk properties from externally provided constitutiveproperties of the fiber and matrix, including extensional stiffness,bending-extension coupling stiffness, bending stiffness, and the like.The laminate bulk properties may then be used to generate aprobabilistic failure envelope for the composite laminate. This providesthe ability to perform non-destructive QA to ensure that individuallamina layup was accomplished according to specifications, and resultsmay be used to identify a numerous laminate properties beyond purelystructural.

U.S. Pat. No. 10,345,272 for Automated calibration of non-destructivetesting equipment by inventors Holmes et al., filed Jul. 13, 2015 andissued Jul. 9, 2019, is directed to a method for auto-calibrating anon-destructive testing instrument. In accordance with some embodiments,the method comprises: (a) determining a first set of coordinates in atest object coordinate system of the test object, the first coordinatesrepresenting a target position on a surface of the test object; (b)storing a calibration file in a memory of the non-destructive testinginstrument, the calibration file containing calibration data which is afunction of structural data representing a three-dimensional structureof the test object in an area containing the target position; (c)calibrating the non-destructive testing instrument using the calibrationdata in the calibration file; and (d) interrogating the target positionusing the calibrated non-destructive testing instrument.

U.S. Pat. No. 5,408,882 for Ultrasonic device and method fornon-destructive evaluation of polymer composites by inventors McKinleyet al., filed Jul. 21, 1993 and issued Apr. 25, 1995, is directed to anultrasonic measurement device and a method for a non-destructiveevaluation of polymer composites having discontinuous fibers distributedtherein. The device has one or a plurality of substantially matchedpairs of transducers disposed on wedge shaped focuser and a relay, thefocuser and relay each have their impedances substantially matched tothat of the polymer composite being analyzed. The device is placed on asurface of the composite with the apexes of the focuser and relay inclose contact with the surface. A velocity of a substantiallylongitudinal ultrasonic wave generated by the first transducer andreceived by the second transducer after its passage through thecomposite is determined at several angles of orientations about a centerpoint, and the measured velocities of the ultrasonic wave are processedthrough a computer having software to determine the physical attributesof the composite, such as weight percentage of fibers present in thecomposite, Young's modulus, shear modulus and Poisson's ratio of thecomposite.

U.S. Pat. No. 10,761,067 for Method and system for non-destructivetesting of curved composites by inventors Jack et al., filed Sep. 8,2015 and issued Sep. 1, 2020, is directed to characterizing andquantifying composite laminate structures, including structures withsurfaces that are curved in two and three dimensions. The embodimentstake a composite laminate of unknown ply stack composition and sequenceand determine various information about the individual plies, such asply stack, orientation, microstructure, and type. The embodiments candistinguish between weave types that may exhibit similar planarstiffness behaviors, but would produce different failure mechanisms.Individual ply information may then be used to derive the laminate bulkproperties from externally provided constitutive properties of the fiberand matrix, including extensional stiffness, bending-extension couplingstiffness, bending stiffness, and the like. The laminate bulk propertiesmay then be used to generate a probabilistic failure envelope for thecomposite laminate. In some embodiments, ply stack type and sequence mayalso be determined for a curved carbon fiber composite using thedisclosed embodiments by adding a rotational stage.

US Patent Publication No. 2020/0047425 for Structural Health Monitoringof Curved Composite Structures Using Ultrasonic Guided Waves byinventors Jahanbin et al., filed Aug. 9, 2018 and published Feb. 13,2020, is directed to systems and methods for non-destructive inspectionof curved composite laminate structures using interface guided waves. Inparticular, if the curved composite laminate structure has a noodle,then the noodle area may be inspected using interface guided waves. Thesystems and methods provide a repeatable and reliable nondestructivetechnique for monitoring the structural health of the noodle area of anadhesively bonded curved composite laminate structure by comparingdetection data acquired from an inspected curved composite laminatestructure with prediction data derived using a simulated curvedcomposite laminate structure.

U.S. Pat. No. 7,975,549 for Method, apparatus and system for inspectinga workpiece having a curved surface by inventors Fetzer et al., filedJun. 19, 2007 and issued Jul. 12, 2011, is directed to a non-destructiveinspection method, apparatus and system are provided for inspecting aworkpiece having a curved surface with at least one predefined radius ofcurvature. The apparatus, such as an inspection probe, includes aplurality of transducer elements positioned in an arcuate configurationhaving a predefined radius of curvature and a curved delay line. Thecurved delay line has an outer arcuate surface having a predefinedradius of curvature that matches the predefined radius of curvature ofthe transducer elements. The curved delay line also has an inner arcuatesurface that has at least one predefined radius of curvature thatmatches the at least one predefined radius of curvature of the curvedsurface of the workpiece. In addition to the inspection probe, thesystem includes an excitative source for triggering the transducerelements to emit signals into the workpiece and a computing device toreceive the return signals.

SUMMARY OF THE INVENTION

The present invention relates to systems and methods of non-destructivetesting using ultrasonic transducers.

It is an object of this invention to provide a system for real-timevisualization of defects within a material using ultrasonicnon-destructive testing.

In one embodiment, the present invention is directed to a system fornon-destructive testing of composite materials, including an ultrasonictransducer in communication with a processor and a display means,wherein the ultrasonic transducer is operable to emit ultrasonic wavesinto and receive ultrasonic waves from a test object to produce scandata, wherein the test object includes a multiplicity of components,with at least one bond layer disposed between two adjacent components,wherein the processor is operable to identify and provide relativepositions of one of more gap regions in the at least one bond layerwithout use of a calibration block, and wherein the processor generatesand presents a graphical representation of the at least one bond layervia the display means.

In another embodiment, the present invention is directed to a system fornon-destructive testing of composite materials, including an ultrasonictransducer in communication with a processor and a display means,wherein the ultrasonic transducer is disposed within a couplingfluid-filled chamber of a transducer housing assembly, wherein theultrasonic transducer is operable to emit ultrasonic waves into andreceive ultrasonic waves from a test object to produce scan data,wherein the test object includes a multiplicity of components, with atleast one bond layer disposed between two adjacent components, whereinthe processor is operable to identify and provide relative positions ofone of more gap regions in the at least one bond layer, and wherein theprocessor generates and presents a graphical representation of the atleast one bond layer via the display means.

In yet another embodiment, the present invention to directed to a systemfor non-destructive testing of composite materials, including anultrasonic transducer in communication with a processor and a displaymeans, wherein the ultrasonic transducer is operable to emit ultrasonicwaves into and receive ultrasonic waves from a test object to producescan data, wherein the test object includes a multiplicity ofcomponents, with at least one bond layer disposed between two adjacentcomponents, wherein the processor is operable identify and providerelative positions of one or more gap regions in a plurality of bondlayers within the test object, and wherein the processor generates andpresents a graphical representation of the at least one bond layer viathe display means.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawing(s) will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 illustrates an orthogonal side view of a transducer housingassembly according to one embodiment of the present invention.

FIG. 2 illustrates an orthogonal side view of a transducer housingassembly according to one embodiment of the present invention.

FIG. 3 illustrates an isometric view of the transducer housing assemblyshown in FIG. 1.

FIG. 4 illustrates a top view of the transducer housing assembly shownin FIG. 1.

FIG. 5 illustrates an isometric exploded view of a transducer housingassembly according to another embodiment of the present invention.

FIG. 6 illustrates an orthogonal exploded view of components of thetransducer housing assembly shown in FIG. 5.

FIG. 7 illustrates an isometric view of a lens housing according to oneembodiment of the present invention.

FIG. 8 illustrates an orthogonal front view of a central housingaccording to one embodiment of the present invention.

FIG. 9 illustrates an orthogonal front view of a lens housing accordingto one embodiment of the present invention.

FIG. 10 illustrates an orthogonal front view of a transducer housingassembly, including the housing shown in FIG. 8 paired with the lenshousing shown in FIG. 9.

FIG. 11 illustrates an orthogonal front view of the transducer housingassembly shown in FIG. 10, with the lens housing secured in the housing.

FIG. 12 illustrates an orthogonal view of a lens housing according toone embodiment of the present invention.

FIG. 13 illustrates an orthogonal side view of a surface offset elementaccording to one embodiment of the present invention.

FIG. 14 illustrates an orthogonal side view of a transducer housingassembly mounted on a robotic arm.

FIG. 15 is a schematic diagram of a transducer housing assembly incommunication with a processor and a display means according to oneembodiment of the present invention.

FIG. 16 illustrates an immersion tank transducer configuration for usein one embodiment of the present invention.

FIG. 17 illustrates a data input screen according to one embodiment ofthe present invention.

FIG. 18 illustrates a group of graphical representations of a testmaterial provided by one embodiment of the present invention.

FIG. 19 illustrates a group of graphical representations of a testmaterial provided by another embodiment of the present invention.

FIG. 20 illustrates a graphical representation of a foreign object in atest material provided by one embodiment of the present invention.

FIG. 21 illustrates an A-scan image generating by one embodiment of thepresent invention.

FIG. 22 illustrates a first step in an algorithm used to calculate thedepth of an adhesive layer according to one embodiment of the presentinvention.

FIG. 23 illustrates a subsequent step in the algorithm used to calculatethe depth of an adhesive layer of FIG. 22.

FIG. 24 illustrates top and bottom surfaces of a bond layer according toone embodiment of the present invention.

FIG. 25 illustrates top and bottom surfaces of a bond layer according toanother embodiment of the present invention.

FIG. 26 illustrates top and bottom surfaces of a bond layer according tostill another embodiment of the present invention.

FIG. 27 illustrates a two-dimensional graphical representation of a bondlayer according to one embodiment of the present invention.

FIG. 28 illustrates a graphical representation of damaged area of amaterial according to one embodiment of the present invention.

FIG. 29 illustrates a graphical representation of damaged area of amaterial according to another embodiment of the present invention.

FIG. 30 illustrates a meshed representation of a damaged area of amaterial according to one embodiment of the present invention.

FIG. 31 illustrates a two-dimensional graphical representation of awrinkle in a test material provided by one embodiment of the presentinvention.

FIG. 32 illustrates a two-dimensional graphical representation with thewrinkle traced and measured by one embodiment of the present invention.

FIG. 33 illustrates a three-dimensional graphical representation of awrinkle in a test material provided by one embodiment of the presentinvention.

FIG. 34 illustrates a three-dimensional graphical representation of awrinkle in a test material provided by another embodiment of the presentinvention.

FIG. 35 illustrates a three-dimensional graphical representationfeaturing an isolated version of the wrinkle of FIG. 34.

FIG. 36 illustrates a two-dimensional view of the wrinkle of FIG. 34.

FIG. 37 illustrates the use of an ultrasonic transducer to monitor thecuring of a test object according to one embodiment of the presentinvention.

FIG. 38 illustrates an unfiltered C-scan of a test material with fibersaligned at 0 degrees according to one embodiment of the presentinvention.

FIG. 39 illustrates an unfiltered C-scan of a test material with fibersaligned at 30 degrees according to one embodiment of the presentinvention.

FIG. 40 illustrates a filtered C-scan of a test material with fibersaligned at 0 degrees according to one embodiment of the presentinvention.

FIG. 41 illustrates a filtered C-scan of a test material with fibersaligned at 30 degrees according to one embodiment of the presentinvention.

FIG. 42 is a schematic diagram of a system of the present invention.

DETAILED DESCRIPTION

The present invention is generally directed to systems and methods ofnon-destructive testing using ultrasonic transducers.

In one embodiment, the present invention is directed to a system fornon-destructive testing of composite materials, including an ultrasonictransducer in communication with a processor and a display means,wherein the ultrasonic transducer is operable to emit ultrasonic wavesinto and receive ultrasonic waves from a test object to produce scandata, wherein the test object includes a multiplicity of components,with at least one bond layer disposed between two adjacent components,wherein the processor is operable to identify and provide relativepositions of one of more gap regions in the at least one bond layerwithout use of a calibration block, and wherein the processor generatesand presents a graphical representation of the at least one bond layervia the display means.

In another embodiment, the present invention is directed to a system fornon-destructive testing of composite materials, including an ultrasonictransducer in communication with a processor and a display means,wherein the ultrasonic transducer is disposed within a couplingfluid-filled chamber of a transducer housing assembly, wherein theultrasonic transducer is operable to emit ultrasonic waves into andreceive ultrasonic waves from a test object to produce scan data,wherein the test object includes a multiplicity of components, with atleast one bond layer disposed between two adjacent components, whereinthe processor is operable to identify and provide relative positions ofone of more gap regions in the at least one bond layer, and wherein theprocessor generates and presents a graphical representation of the atleast one bond layer via the display means.

In yet another embodiment, the present invention to directed to a systemfor non-destructive testing of composite materials, including anultrasonic transducer in communication with a processor and a displaymeans, wherein the ultrasonic transducer is operable to emit ultrasonicwaves into and receive ultrasonic waves from a test object to producescan data, wherein the test object includes a multiplicity ofcomponents, with at least one bond layer disposed between two adjacentcomponents, wherein the processor is operable identify and providerelative positions of one or more gap regions in a plurality of bondlayers within the test object, and wherein the processor generates andpresents a graphical representation of the at least one bond layer viathe display means.

Ultrasonic testing is one of the most popular methods of non-destructivetesting (NDT), also known as non-destructive inspection (NDI) ornon-destructive evaluation (NDE). Ultrasonic testing involves theemission of ultrasonic waves into a test material by a transducer andthe subsequent sensing of reflecting or transmitted waves by a receiver.In pulse-echo, or reflection, configurations, the ultrasonic energy isintroduced to and transmitted through the surface of the test materialin waves. The use of such systems typically requires an acoustic medium(e.g., water, gel) to bridge the gap between the transducer and the testmaterial. As the waves propagate through the thickness of the testmaterial, discontinuities within the test material (due to materialchanges, cracks, delaminations, foreign objects, etc.) cause areflection of the wave, which can then be detected by the transducer anddisplayed or characterized. In contrast, in through transmission, orattenuation, configurations, a transducer generates high frequencyultrasonic energy, which is transmitted through one side of a testmaterial and then received by a corresponding receiver on the oppositeside of the test material. As the waves propagate through the thicknessof the test material, discontinuities within the test material may causewaves in some areas to be slowed or fully attenuated before they reachthe receiver. The receiver can then characterize the test material bymeasuring the degree of attenuation of the ultrasonic wave.

When the ultrasonic waves emitted by an ultrasonic transducer contact amaterial with different properties than the ones they are initiallytraveling through, some waves are reflected back in accordance withEquation 1 below.

$\begin{matrix}{R = \frac{Z_{2} - Z_{1}}{Z_{1} + Z_{2}}} & \left( {{Equation}\mspace{14mu} 1} \right)\end{matrix}$

In Equation 1, R is a reflection coefficient, which is a decimal valuerepresenting the percentage of waves reflected at the boundary betweentwo materials. Z₁ and Z₂ are the acoustic impedances of the twomaterials that make up the material boundary. The acoustic impedance ofa material is found by multiplying the speed of sound for the materialby its density. Additionally, the speed of sound for the material isfound by dividing the square root of the Young's modulus of the materialby the square root of the density of the material. Therefore, based onthe percentage of waves reflected, a user is able to calculate thereflection coefficient for the interaction. If the acoustic impedancefor one material is known, the identity of the other material is able tofound using Equation 1.

In selecting ultrasonic inspection systems, the constraints ofportability and robustness are often inversely proportional to highresolution and fidelity. When attempting to optimize both portabilityand robustness, most inspectors currently select a contact transducer.Contact transducers allow an inspector to quickly place a thin gel on apart to be inspected and place the transducer in intimate contact withthe part. Data can be quickly gathered and at the same time, the systemcan operate on a variety of surfaces and environmental conditions. Theprimary downside of this approach is the resolution of the acquireddata. The planar resolution of the transducer is dictated by thephysical footprint of the transducer. This footprint can be mitigated byfabricating smaller and smaller transducers. The through-thicknessresolution of the transducer, however, is determined by the frequency ofthe transducer and the power with which it can be fired. As atransducer's planar dimension is reduced, both the power that can besent to fire the transducer and the frequency is simultaneously reduced.Thus, improvements to planar resolution are in direct conflict withimprovements in through thickness resolution.

An alternative to the contact transducer is a spherically focusedtransducer. These transducers are capable of operating at highfrequencies (25-50 MHz) and have a planar resolution as fine as can bemachined into the transducer housing lens, which may be less than 1/10thof a millimeter. However, spherically focused transducers can onlyoperate when the transducer is fully acoustically coupled to the surfaceof a component being inspected. Acoustically coupling the transducer tothe test material requires immersing the transducer in an acousticmedium while ensuring the transducer has a viable acoustic path betweenit and the surface to be tested. Water is the most widely used acousticmedium for immersion transducers, as the difference in acousticimpedance between the water and transducer lens is minimal.

Currently, there are two main techniques to achieve a viable acousticcoupling water path: full immersion tank testing or water jets. The fullimmersion tank requires the part to be submerged in water, thuspreventing many larger components, such as aircraft wings and fuselages,from being tested without a substantial (and often impractical)infrastructure investment. Water jets, on the other hand, require waterto be spraying in all directions, which causes water to pool under thecomponent being scanned. Water jets therefore also requireinfrastructure investments, often in the form of grates to collect thesprayed water, pumps to circulate the water, and framing to protectequipment in the area that can be damaged by water.

One alternative to the use of traditional water jets is a “bubbler”. Touse a bubbler, a temporary watertight box is built around a region of acomponent to be scanned for inspection. Water is then poured into acolumn that houses the transducer and is allowed to slowly leak out froma base of the box. This approach requires a new box to be installed atevery new location for the scan. In order for a bubbler to work, themembrane must be pressed tightly against the object to be tested, aswater leaks out slowly enough from the bubbler that it cannot maintainthe blast pressure necessary to allow the device to be placed at anoffset from the test material. Not only does this create the risk ofimpact between the bubbler and the test material, which may causedamage, but it also greatly reduces the resolution of the device.Bubblers rely on permeable membranes that slowly allow the water to leakout, but when the bubbler is operating and the membrane is pressedfirmly against the test surface, the systems cannot effectivelydistinguish between waves in the membrane and in the test material,rendering the devices less effective if not entirely inoperable.Furthermore, bubblers suffer from similar drawbacks as traditional waterjets, in that they require water to be pumped in constantly and requirea means to catch leaking water. Additionally, full immersion,traditional water jets, and the bubbler all require the test material tobe exposed to water, which is undesirable in some situations.

Traditional water jets and bubblers also suffer similar problems ofbeing unable to scan hard to reach areas of a device. Hard to reachareas are often semi-contained within a device or component to be testedand therefore, the use of traditional water jets is highly likely tocause water to pool within the device, which may cause damage or bedifficult to pump out. Furthermore, both traditional water jet systemsand bubblers require the continuous pumping in of water via a watercolumn. However, the need for this water column eliminates the abilityof those devices to effectively navigate to hard-to-reach areas of adevice or component to be tested.

As of yet, no other efforts to produce a robust functional ultrasonicscanner utilizing water-filled chambers have been successful. Someexisting systems require the chamber to leak around a rolling ball,through a permeable membrane, or otherwise, to span the gap between thechamber and the surface to be measured. Such systems still require aflow of water into the chamber to replenish the water loss to maintainthe acoustic coupling and require contact between the water and the testmaterial. Other systems sacrifice the use of a spherically focusedtransducer and therefore have decreased resolution. Still other systemshave fixed focal lengths, and other systems have fixed lengths of lenshousing and lens that preclude reaching portions of surfaces forscanning.

Ultrasonic testing typically results in the formation of multiple typesof scan data, as the transducer emits waves into different sections ofthe test material, such as A-scans, B-scans, and C-scans. An A-scan isformed for each individually scanned point of the test material. A-scanstypically show a signal amplitude as a function of time, wherein signalsappearing later in time are reflected from boundary changes at greaterdepths in the material and the presence of greater than two signals(more than the initial entry into the test material and the reflectionoff the back wall of the test material) indicates the presence of adefect, or internal layering within the test material. A-scans can beuseful in determining whether a defect or layer boundary is present at aparticular point in an object, but lacks specificity regarding the sizeor type of defect in question and can only characterize one specificarea of the material.

B-scans are constructed as combinations of individual A-scans as anultrasonic testing device is swept along an axis of the test material.As the ultrasonic testing device is moved, the B-scan is able to form across-sectional view of the device, indicating at what depth defects arefound based on the peaks of the A-scan for each point along the testmaterial. This creates a sort of side view of the test material, whichis useful for providing information regarding impact damage anddelaminations.

A C-scan provides a cross-sectional view of the test material that isorthogonal to that of the B-scan. C-scans combine A-scans for differentX and Y coordinates along a plane to produce a cross sectional view thatcan provide not only position data for an internal defect or layer, butalso an indication of the defect or layer's cross-sectional area at agiven depth. C-scans are formed by selecting a gate start time and agate end time and then obtaining intensity information within the gateregion for every A-scan that is taken. Some systems utilize phase arraytechnology with transducers aimed in different directions, such as thatthe system is able to gain a wider array of A-scans before thetransducer is moved across each point of the test area. C-scans arehowever, two dimensional images and are unable to accurately provide forthe depth of a defect or precisely observe defects that would appearmore predominately in a view orthogonal to the cross-sections of theC-scans.

In order to find irregularities within a test material, most currentsystems rely on the use of calibration blocks, with the A-scan, B-scan,and C-scans of current systems being incapable of accurately detectingmany imperfections in isolation. Before testing, the testing device isused on one or more calibration blocks, which typically are either anexemplary form of the material to be tested or a material with knowndefects. Traditional ultrasonic inspection systems use this calibrationmethod as a means of comparison in determining whether the signalsreflected from the test material match or differ from those of thecalibration block. However, reliance on calibration blocks weakens theability to specifically indicate important properties of a testmaterial. For example, porosity testing, traditional systems mayrecognize calibration blocks with porosities of 0.2, 0.4 and 0.6, but atest material which most closely aligns with the 0.4 porositycalibration block may still have a porosity of anywhere between 0.3 and0.5, with further specificity being limited. Furthermore, testing usingcalibration blocks may be hindered by unknown flaws in the calibrationblocks or unconsidered confounding variables that differ between thecalibration blocks and the actual test material. Therefore, a system isneeded that is capable of directly determining qualities of a material,such as ply orientation, porosity, bond line thickness, the presence ofwrinkles, unevenness in the bond line, or other important physicalproperties of a test material without reference to a calibration block.

Due to their high strength-to-weight ratios, composites are becomingincreasingly common, particularly for structural applications in theaerospace, automotive, and defense industries. A composite is defined asthe combination of two or more materials to form a new material,including, but not limited to, concrete, straw reinforced clay bricks,carbon fiber laminates, and fiberglass. Manufacturing defects as well asdamage caused during use of the composite can have a significant impacton the laminate's structural performance and sometimes lead tostructural failure. Damage to a composite can frequently occur as aresult of hail strikes, lightning, bird collisions, mishandling of thepart, or general fatigue. Examples of defects that can lead to thefailure of a composite material during use include foreign objectswithin the material, insufficient bonding between the layers of thecomposite, wrinkling of the layers of the composite, delamination withinat least one layer of the composite, incomplete curing of the composite,and excessively large pores within the composite. Therefore, propertiessuch as the bond line thickness, porosity, ply type, and weave type ofthe composite can have significant effects on the overall materialproperties and performance of a composite structure, and they may evenserve as crack initiation points.

Current portable transducer systems are inadequate for properlycharacterizing composite laminates due to the acoustic impedance andthickness of many composite materials. Composite laminates typicallyrange between several millimeters to nearly ¾ of an inch in thickness,frequently with individual lamina with a thickness of about ¼ mm. As ageneral rule, the wavelength of waves used to detect individual laminashould be no larger than half the thickness of the material, or less thematerial may go entirely unnoticed by the wave. Therefore, due to thecombination of the small layer size in composites and high attenuationof waves within the composite, in order to characterize meaningfuldefects within or between layers of these composites with sufficientresolution, transducers need to be able to emit frequencies between 7.5and 15 MHz. This is an issue for current portable transducer systems,which are generally only able to emit frequencies on the order of about2-3 MHz. Many existing systems, furthermore, only use frequencies up toapproximately 5 MHz, as this is understood to approximate the naturalfrequency of the material being tested. However, limiting the frequencyto 5 MHz or lower limits the resolution of the scan, leading systems tooverlook potentially relevant features and flaws. An alternativesolution to portable transducers is an immersion type system, whichusually involves completely immersing the test material in a water tankor continually spraying water jets at the material in order to maintainsufficient acoustic coupling between the transducer and the surface ofthe test material. However, immersion techniques are typicallyinconvenient in terms of both a large cost and additional necessaryset-up time for testing.

As the frequency of the transducer increases, the resolution quality ofthe transducer increases. However, as the frequency of the transducerincreases, the depth of a material visible to the system decreases. Inone embodiment, the transducer is able to operate at frequencies between0.5 MHz and 50 MHz. In another embodiment, the transducer is able tooperate at frequencies between 1 and 25 MHz. In yet another embodiment,the transducer is able to operate at frequencies between 5 and 15 MHz.In still another embodiment, the transducer is able to operate between10 and 15 MHz. In a preferred embodiment, the transducer operatesbetween 7.5 and 15 MHz.

Additionally, traditional ultrasonic testing devices utilize calibrationblocks. Before testing, the testing device is used on one or morecalibration blocks, which typically are either an exemplary form of thematerial to be tested or a material with known defects. Traditionalultrasonic inspection systems use this calibration method as a means ofcomparison in determining whether the signals reflected from the testmaterial match or differ from those of the calibration block. However,reliance on calibration blocks weakens the ability to specificallyindicate important properties of a test material. For example, porositytesting, traditional systems often recognize calibration blocks withporosities of 0.2, 0.4 and 0.6, but a test material which most closelyaligns with the 0.4 porosity calibration block could still have aporosity of anywhere between 0.3 and 0.5, with further specificity beinglimited. Furthermore, testing using calibration blocks may be hinderedby unknown flaws in the calibration blocks or unconsidered confoundingvariables that differ between the calibration blocks and the actual testmaterial. Therefore, a system is needed that is capable of directlydetermining qualities of a material, such as ply orientation, porosity,bond line thickness, the presence of wrinkles, unevenness in the bondline, or other important physical properties of a composite materialwithout reference to a calibration block.

In one embodiment, a portable transducer housing assembly contains atransducer used to scan a test material. The portable transducer housingassembly includes a central housing with an interior sealed chamber,with the transducer disposed within the interior sealed chamber. Theinterior sealed chamber is detachably connected to a fluid pump, whichis operable to both pump air out of the interior sealed chamber and pumpwater or other coupling fluid into the interior sealed chamber. At afront end of the central housing is a membrane, which seals the interiorsealed chamber. The membrane is acoustically transparent or acousticallytranslucent to the coupling fluid within the interior sealed chamber. Inone embodiment, the transducer is movable relative to the centralhousing of the portable transduce housing assembly, which allows a userto adjust the focus of the device depending on the size and nature ofthe transducer and the nature of the test material.

In one embodiment, the portable transducer housing assembly used by thepresent system is placed at an offset from the test material, with anexternal couplant disposed between the membrane of the portabletransducer housing assembly and the test material. In one embodiment,the external couplant is an acoustic gel, such as glycerin, couplantD12, couplant H, a shear wave couplant, or another suitable acousticgel. In one embodiment, at least one offset element extendslongitudinally outwardly from the central housing toward the testmaterial in order to ensure that the portable transducer housingassembly does not come into harmful contact with the test material andthat the portable transducer housing assembly is kept at a minimum fixedoffset from the test material.

In one embodiment, the distance that the transducer housing assembly isoffset from the test material is determined using a calibration wave. Aninitial wave is transmitted via the transducer into the test material.Time of flight data is gathered regarding ultrasonic waves reflectingoff of a membrane covering the opening of the lens housing, wavesreflecting off the front surface of the test material, and wavesreflecting off the back surface of the test material. Without the needto input material properties or dimensions of the test material, thetransducer housing assembly is able to automatically offset by a fixeddistance from the test material based on the results of the time offlight data. In another embodiment, the material properties of the testmaterial, such as the speed of sound, and dimensional data of the testmaterial, such as the thickness, is manually entered, allowing thetransducer housing assembly to automatically offset by a fixed distancefrom the test material without the need for a calibration wave.

In one embodiment, the transducer housing assembly mounted on a roboticarm. The transducer housing assembly includes a mounting bracket with anattachment bore able to receive a screw, bolt, pin, or other affixingmeans attached to the robotic arm. The robotic arm both allows thetransducer housing assembly to reach tighter spaces and allows thedevice to be held steadily for the duration of the testing, increasingthe accuracy of the test. In another embodiment, the mounting bracket isattached to a translation stage. The translation stage operates to movethe transducer housing assembly to different positions along an X-Yplane. This is especially advantageous in situations wherein theoperator desires to scan large sections of a relatively flat testmaterial.

In one embodiment, the transducer housing assembly is attached to anarray element. In another embodiment, the array element includesattachment points for more than one transducer housing assembly,allowing multiple transducer housing assemblies to be attached to asingle array element, which acts as an array of transducers. The arrayof transducers is therefore able to scan multiple points of a testmaterial simultaneously, with each individual transducer housingassembly being adjustable, so as to allow the array of transducers toscan components with uneven surfaces or scan components having multipledifferent material types.

In another embodiment, the transducer housing assembly is manuallyoperated. By way of example, the transducer housing assembly is placedinto an assembly attached to the test material. An operator is then ableto manually slide the transducer housing assembly within the assemblywhile the assembly ensures that the transducer housing assembly remainsat a substantially fixed distance from the test material. In stillanother embodiment, the transducer housing assembly is able toautomatically move to a plurality of different points on the test objectbased on preset position data entered into a computer or attacheddisplay.

In another embodiment, the transducer housing assembly lacks membrane,leaving the interior chamber unsealed. The water is pumped in at a highflow rate, allowing water jets to form spray the test material,acoustically coupling the transducer to the test material. In yetanother embodiment, the transducer is not disposed within a transducerhousing assembly and is placed in an immersion tank in order to ensureacoustic coupling with the test material.

In one embodiment, the transducer housing assembly is attached to aconnection receiving end. In another embodiment, the connectionreceiving end is connected to a computer or another processor and awaveform generator, such as a pulser receiver, via a cable. The computeror processor includes a display means, such as a monitor or a touchscreen. In one embodiment, a single waveform generator is able toconnect to multiple transducer housing assemblies simultaneously. In oneembodiment, the connection receiving end is a UHF connector, a BayonetNeill-Concelman (BNC) connector, or a Universal Serial Bus (USB)connector. In another embodiment, the connection receiving end is awireless adapter, allowing the transducer housing assembly 4 to wirelessconnect with the pulser receiver. The pulser receiver is connected to acomputer, having a processor and memory. Furthermore, the computerincludes display means for outputting graphical results of ultrasonictesting performed using the transducer housing assembly. In yet anotherembodiment, the computer is also connected with the robotic arm,translation stage, or array element to which the transducer housingassembly 4 is attached and is operable to issue control instructions tothe robotic arm, translation stage, or array element.

The computer is connected to a display means able to display a graphicaluser interface (GUI), which is able to display the results of thetesting after processing by the pulser receiver. In another embodiment,a display is directly mounted to the transducer housing assembly, whichallows results to be displayed to the user of the transducer housingassembly without the operator needing to step away to check thecomputer. The GUI is able to accept a variety of input factors beforeeach test, including the operator's name, the time, and materialproperties including the speed of sound of the material to be tested,the thickness of the material to be tested, the stiffness of thematerial to be tested, and/or the type of material to be tested. In oneembodiment, the GUI is also able to accept a range of locations and arun time, indicating where the robotic arm, the array element, or thetranslation stage should position itself for testing.

The present system is capable of displaying information regarding avariety of factors of a laminate, including the location and depth offoreign objects within the laminate, the ply orientation of thelaminate, the location of wrinkles within the laminate, the thickness ofthe bond line of the laminate, areas of incomplete bonding along thebond line of the laminate, the porosity of the laminate, and thelocation, depth, and size of internal defects and areas of delaminationwithin the laminate.

1. Transducer

FIG. 1 illustrates an orthogonal side view of a transducer housingassembly 4 according to one embodiment of the present invention. Thetransducer housing assembly 4 includes a central housing 6 with a frontportion 10 and a back portion 8. In one embodiment, the front portion 10and back portion 8 are hollow cylindrical pieces and are integrallyformed with each other. Alternatively, the front portion 10 and backportion 8 are not integrally formed but are separately formed and arejoined together via any chemical and/or mechanical means known in theart. In another embodiment, the front portion 10 and back portion 8 areanother shape, such as rectangular prisms. In one embodiment, thediameter of the front portion 10 is greater than that of the backportion 8, with the diameter of the central housing 6 tapering downbetween the front portion 10 and back portion 8 at a midsection 9. Thecentral housing 6 is attached to a fluid connector 24. In oneembodiment, the fluid connector 24 is attached to the front portion 10of the central housing 6, while in another embodiment, the fluidconnector 24 is attached to the midsection 9 or back portion 8 of thecentral housing 6. In one embodiment, a mounting bracket 26 extends fromthe front portion 10 of the central housing 6. In another embodiment,the mounting bracket 26 extends from the midsection 9 or back portion 8of the central housing 6.

The front portion 10 of the central housing 6 is connected to a lenshousing 20, which extends outwardly from the front end of the centralhousing 6. The front end of the lens housing 20 includes an opening 22.In one embodiment, at least one surface offset element 28 extends fromthe front end of the central housing 6. In another embodiment, thesurface offset elements 28 extend outwardly directly from the lenshousing 20. Transducer is disposed within the central housing 6. In someembodiments, the transducer is directly attached to an elongate member52. The elongate member 52 is attached to the central housing 6 by meansof a coupling element 16. In one embodiment, the position of theelongate member 52, and therefore the transducer, can be adjustedrelative to the central housing 6 by rotating or otherwise adjusting thecoupling element 16.

In one embodiment, the elongate member 52 and coupling element 16include a metal material, such as, but not limited to, steel oraluminum. In another embodiment, the elongate member 52 and couplingelement 16 are formed of the same metal material. Forming both theelongate member 52 and coupling element 16 from the same metal materialis advantageous, as it prevents one of the elements acting as a cathodeor an anode, which would allow for galvanic cell activity in thetransducer housing assembly 4, shortening the useful life of the device.In one embodiment, the central housing 6 is formed from a plastic, suchas polycarbonate or polyethylene. In another embodiment, the centralhousing 6 is formed via 3D printing of the device using an ultraviolet(UV) curable polymer, which is then cured after formation.

In one embodiment, as shown in FIG. 1, the mounting bracket 26 includesa first plane 262 extending away from the central housing 6 at an angleand a second plane 263 extending from the end of the first plane 262 ina direction substantially parallel to a central axis of the transducerhousing assembly 4. In another embodiment, as shown in FIG. 5, themounting bracket 26 is a substantially rectangular piece disposedbetween and orthogonal to the front portion 10 and back portion 8 of thecentral housing 6. As can be seen in FIG. 2, in other embodiments, themounting bracket 26 takes different shapes, depending on the device towhich it is to be attached.

FIG. 3 illustrates an isometric view of the transducer housing assembly4 shown in FIG. 1. FIG. 4 illustrates a top view of the transducerhousing assembly shown in FIG. 1. As can be seen in FIGS. 3 and 4, inone embodiment, the transducer housing assembly 4 includes three surfaceoffset elements 28. In one embodiment, the mounting bracket 26 includesat least one attachment bore 261

FIG. 5 illustrates an isometric exploded view of a transducer housingassembly 4 according to another embodiment of the present invention. Inone embodiment, the fluid connector 24 is attached to the centralhousing 6 of the transducer housing assembly 4 by connecting to aconnection port 34. In one embodiment, the fluid connector 24 connectsto the connection port 34 by means of threading located on the outsidesurface of the fluid connector 24 and the interior surface of theconnector port 34.

In one embodiment, the coupling element 16 is a hollow cylinder and theelongate member 52 extends through the coupling element 16. The elongatemember 52 and the coupling element 16 are held together by frictionalcontact between the outside surface of the search tube 52 and theinterior surface of the coupling element. As shown in FIG. 6, in anotherembodiment, the elongate member 52 is secured to the coupling element 16by a securing element 54. In one embodiment, the securing element 54 isa screw, bolt, or compressible pin. In one embodiment, the elongatemember 52 is a hollow cylinder with the transducer 50 being frictionallyengaged within a front end of the elongate member 52.

In one embodiment, the coupling element 16 connects to the centralhousing 6 by means of threading on part of the surface of the couplingelement 16 and on the inner surface of a first opening 12 in the backportion 8 of the central housing 6. In another embodiment, when thecoupling element 16 is engaged with the central housing 6, the couplingelement 16 can be rotated so as move the coupling element 16 and theelongate member 52 longitudinally relative to the central housing 6. Inyet another embodiment, the securing element 54 can be removed,compressed or otherwise altered, which allows the coupling element 16and the elongate member 52 to move longitudinally relative to thecentral housing 6. By moving the elongate member 52 longitudinallyrelative to the central housing 6, the position of the transducer 50 isable to be changed, which allows for accommodation of a range of sizesfor transducers 50, as well as greater precision in the focusing on thetransducer.

In one embodiment, the first opening 12 includes sealing elements, whichprevent fluid leakage through the first opening 12. In one embodiment,the sealing elements include O-rings lining the inner surface of thefirst opening 12. In another embodiment, the chamber within the centralhousing 6 is not fully sealed during operation, with either the back endof the central housing 6 or the interface with the fluid connector 24being left unsealed. The option to use the transducer housing assembly 4without sealing the chamber of the central housing provides flexibilityin the parts used to construct the device, including allowing for thereduction of manufacturing cost. However, for use of the transducerhousing assembly 4 that involves putting the transducer housing assembly4 at an angle, it is advisable to sealed the interior chamber to preventfluid leakage, which could cause decoupling of the transducer to thetest material.

The front portion 10 of the central housing 6 further includes a secondopening 18. The lens housing 20 is inserted into the second opening 18in order to engage the lens housing 20 with the central housing 6. Inone embodiment, the lens housing 20 and central housing 6 are engaged bymeans of threading on the exterior surface of the lens housing 20 and onthe interior surface of the second opening 18. In another embodiment,the lens opening 20 includes annular or helical grooves 58, within whichsealing elements are attached. When the lens opening 20 placed into thesecond opening 18, the sealing elements engage with the interior surfaceof the second opening 18 and form a fluid-tight seal. In one embodiment,the sealing elements are O-rings. In yet another embodiment, the secondopening 18 includes at least one engagement notch 32 and the lenshousing 20 includes at least one engagement protrusion 30, as shown inFIG. 7. As shown in FIGS. 8-11, in order for the lens housing 20 to beplaced within the second opening 18, the at least one engagementprotrusion 30 of the lens housing 20 must align with the at least oneengagement notch 32 of the second opening 18. After the lens housing 20is placed within the second opening 18, the lens housing 20 is turnedsuch that the at least one engagement protrusion 30 no longer alignswith the at least one engagement notch 32. In one embodiment, the lenshousing 20 is easily separated from the central housing 6 by twistingthe lens housing 20 and pulling it out. This is advantageous in theevent that the lens housing 20 becomes damaged and needs to be replaced,or where lens housings 20 of different sizes are needed in order examinedifferent parts of a component.

FIG. 6 illustrates an orthogonal exploded view of components of thetransducer housing assembly shown in FIG. 5. The fluid connector 24 isable to be connected to one end of a conduit 36, such as a hose or apipe. In on embodiment, the other end of the conduit 36 is connected toa fluid pump or fluid reservoir, from which fluid is able to beintroduced through the conduit 36 and the fluid connector 24 into thesealed chamber. In another embodiment, the transducer housing assembly 4is not connected to a fluid pump and fluid is added to the centralhousing 6 by other means, such as manual pouring.

In one embodiment, the fluid connector 24 includes a pressure reliefvalve, which allows fluid to escape when the volume of fluid exceeds thevolume of the sealed chamber. The pressure relief valve thereforeadvantageously provides an adjustable volume of fluid into the sealedchamber, depending on the distance between the transducer 50 and thefront end of the central housing 6. In one embodiment, the fluidconnector 24 is able to be connected to a pump and air is pumped out ofthe sealed chamber before or while filling the chamber with a couplingfluid. Pumping out air helps to assure a lack of bubbles in the fluid,which improves the acoustic coupling path between the transducer 50 anda component to be tested. Furthermore, after testing has completed, theair pump is able to be used to pump air into sealed chamber, whichassists in removing remaining fluid, reducing prolonged exposure to thecoupling fluid, which could cause damage to the transducer housingassembly, such as corrosion.

FIG. 12 illustrates an orthogonal view of a lens housing 20 according toone embodiment of the present invention. A membrane 38 is placed overthe front end of the lens housing 20. The membrane 38 creates afluid-tight seal on the front end of the lens-housing 20. When the lenshousing 20 with the membrane 38 is placed into the central housing 6, asealed chamber is formed within the central housing 6. The sealedchamber is a fluid-tight chamber, which is sealed by a combination ofthe interface between the coupling element 16 and first opening 12 ofthe back portion 8 of the central housing 6, the interface between thelens housing 20 and the second opening 18 of the front portion 10 of thecentral housing 6, the membrane 38, and the fluid connector 24. In oneembodiment, the membrane 38 is secured to the lens housing 20 by atleast one retainer 40. In one embodiment, the at least one retainer 40includes at least one O-ring surrounding a portion of the lens housing20 and pressing the membrane 38 tightly against the lens housing 20.Advantageously, in the event that membrane 38 is punctured or otherwiseis unable to effectively seal the sealed chamber, it may easily bereplaced by removing the retainer 40, refitting a new membrane, and thenreapplying the retainer 40.

The membrane 38 is acoustically transparent or translucent with respectto fluid in the sealed chamber. The material used for the membrane 38 isselected to have a similar acoustic impedance, and therefore similarstiffness and density, as the fluid in the sealed chamber. In oneembodiment, the fluid is water or another fluid with an index ofrefraction approximately equal to 1. In another embodiment, the index ofrefraction of the membrane 38 is between 0.9 and 1.2. In yet anotherembodiment, the membrane is made from AQUALENE.

As the frequency of the transducer 50 increases, the temporal resolutionquality of the transducer increases. However, as the frequency of thetransducer 50 increases, the depth of a material visible to the systemdecreases due to high frequency attenuation. In one embodiment, thetransducer 50 is able to operate at frequencies between 1 and 50 MHz. Ina preferred embodiment, the transducer 50 operates between 5 and 15 MHz.

external couplant can be used to fill the gap between the transducerhousing assembly 4 and the test material. In one embodiment, theexternal couplant is an acoustic gel, such as glycerin, couplant D12,couplant H, a shear wave couplant, or another suitable acoustic gel.

FIG. 13 illustrates an orthogonal side view of a surface offset elementaccording to one embodiment of the present invention. In one embodiment,the surface offset elements 28 include pins 281 attached to a biasingmember 282. The biasing member 282 allows the surface offset elements 28to retract when pressed against the surface of a test material.Furthermore, when the pin 281 is pressed against a test material, thebiasing member 282 is able to absorb some of the displacement that wouldotherwise be imparted to the test material through a force or thetransducer housing assembly 4, preventing potential damage to both thetransducer housing assembly 4 and the test material. In one embodiment,the degree to which the surface offset elements 28 are able to retractis limited by a stop. When the front of the transducer housing assembly4 is pressed against a component to be tested, the surface offsetelements 28 contact the component first, which prevents damage to thecomponent or to the transducer housing assembly 4 that can be caused byquick and direct contact between the lens housing 20 and the component.Furthermore, by providing a stop to limit the retraction of the surfaceoffset elements 28, the lens housing 20 is able to stay at a fixed andknown distance from the component, which allows for improved accuracyduring the testing process. In another embodiment, the surface offsetelements 28 are threadably connected to the front portion 10 of thecentral housing 6 and can be manually adjusted before use with differenttest materials. In one embodiment, the transducer housing assembly 4operates at an offset distance from the test material approximatelyequal to one half the thickness of the test material.

In one embodiment, the distance that the transducer housing assembly 4is offset from the test material is determined using a calibration wave.An initial wave is transmitted via the transducer into the testmaterial. Time of flight data is gathered regarding ultrasonic wavesreflecting off of a membrane covering the opening 22 of the lens housing20, waves reflecting off the front surface of the test material, andwaves reflecting off the back surface of the test material. Without theneed to input material properties or dimensions of the test material,the transducer housing assembly 4 is able to automatically offset by afixed distance from the test material based on the results of the timeof flight data. In another embodiment, the material properties of thetest material, such as the speed of sound, and dimensional data of thetest material, such as the thickness, is manually entered, allowing thetransducer housing assembly 4 to automatically offset by a fixeddistance from the test material without the need for a calibration wave.

FIG. 14 illustrates an orthogonal side view of a transducer housingassembly mounted on a robotic arm. The attachment bore 261 is able toreceive a screw, bolt, pin, or other affixing means attached to arobotic arm 48. The robotic arm 48 both allows the transducer housingassembly 4 to reach tighter spaces and allows the device to be heldsteadily for the duration of the testing, increasing the accuracy of thetest. In another embodiment, the mounting bracket 26 is attached to atranslation stage. The translation stage operates to move the transducerhousing assembly 4 to different positions along an X-Y plane. This isespecially advantageous in situations wherein the operator desires toscan large sections of a relatively flat test material.

In one embodiment, the transducer housing assembly 4 is attached to anarray element. In another embodiment, the array element includesattachment points for more than one transducer housing assembly 4,allowing multiple transducer housing assemblies 4 to be attached to asingle array element, which acts as an array of transducers. The arrayof transducers is therefore able to scan multiple points of a testmaterial simultaneously, with each individual transducer housingassembly 4 being adjustable, so as to allow the array of transducers toscan components with uneven surfaces or scan components having multipledifferent material types.

In another embodiment, the transducer housing assembly 4 is manuallyoperated. By way of example, the transducer housing assembly 4 may beplaced into an assembly attached to the test material. An operator isthen able to manually slide the transducer housing assembly 4 within theassembly while the assembly ensures that the transducer housing assembly4 remains at a substantially fixed distance from the test material. Instill another embodiment, the transducer housing assembly 4 is able toautomatically move to a plurality of different points on the test objectbased on preset position data entered into a computer or attacheddisplay.

FIG. 15 is a schematic diagram of a transducer housing assembly incommunication with a processor and a display means according to oneembodiment of the present invention. The transducer housing assembly 4is connected to a pulser receiver 35, which generates a waveform fromthe signal produced by the transducer within the transducer housingassembly 4. The waveform is then processed by a processor 42 incommunication with the pulser receiver 35 to produce one or morevisualizations of the data that are displayed by a display means 45.

FIG. 16 illustrates an immersion tank transducer configuration for usein one embodiment of the present invention. In one embodiment, thetransducer 50 used to produce the ultrasonic waves and receive a signalfrom a test material 55 is not within a transducer housing assembly 4and is acoustically coupled with the test material 55 via an immersiontank 60. The transducer 50 is connected to a pulser receiver 35, whichgenerates a waveform from the signal produced by the transducer 50. Thewaveform is then processed by a processor 42 in communication with thepulser receiver 35 to produce one or more visualizations of the datathat are displayed by a display means 45.

2. Data Input and Calibration

FIG. 17 illustrates a data input screen according to one embodiment ofthe present invention. As shown in FIG. 17, the GUI allows a user toenter parameters for the test material to be tested. In one embodiment,the user is able to select materials from a predetermined materialdatabase, which includes specific listings mentioning the fiber width,fiber wrap, number of layers of the composite, layer thickness, fiberareal density, speed of sound, stiffness, and/or other material andphysical properties of the material, in addition to more generallistings, such as “fiberglass” or “carbon fiber,” which providequantities like the speed of sound for the material without moredetailed information regarding the layering of the material. In anotherembodiment, the user enters mechanical and physical properties of thetest material manually, selecting qualities such as the speed of sound,stiffness, thickness of the material, and/or other material and physicalproperties of the material. The user is able to select the option tosave manually entered materials into the material database in order tomore easily select those materials at a later date. In yet anotherembodiment, the GUI includes an option to use a calibration wave togather the parameters of the material and no material parameters need tobe entered by the user before testing of the device.

In one embodiment, a user is able to select parameters for the dataoutput, such as the X, Y, and Z resolution of the scan via a coordinateselection module 31. Additionally, for situations in which thetransducer is coupled to a robotic arm, translation stage, or arrayelement, the user is able to select an X, Y, or Z position at which thescan should commence or a range of X, Y, and Z positions across whichthe transducer should move via the coordinate selection module 31. Inone embodiment, the range of X, Y, and Z positions is selected bymanually entering data points for each coordinate through the coordinateselection module 31. In another embodiment, the GUI features a virtualprojection of a plane and allows the user to drag and drop a virtualdevice in order to indicate the path along which the transducer shouldmove.

In one embodiment, the user is able to select a z-gate start time and az-gate end time, defining a gate region for the scan via a z-gateselection module 21. Selecting the gate region allows the system todetermine between which depths of the test material to take intensitydata from A-scans in order to compile a C-scan for the test material. Inanother embodiment, the gate is moved through the entirety of theA-scan, creating a plurality of C-scans that form a 3-D image of thematerial.

Existing systems utilize a method of gating, wherein a designated gatedregion is the only portion of a waveform that is retrieved and processedby the system. Therefore, in order to analyze, for example, 50 differentgated regions within a material, existing systems would need to scan thematerial 50 different times, one for each designated gate region. Thepresent system improves upon existing systems by retrieving the fullwaveform for each A-scan of a material. References to selection of az-gate start time, z-gate end time, or gate regions in the presentapplication refer not to a hardware limitation on what portions of thewaveform are designated to be received, but instead refer to which areasof the fully retrieved waveform are analyzed for a particular purpose.By analyzing the full waveform from a material, the present systemimproves upon existing systems both in the amount of time taken in toscan the material and the resolution of images generated for thematerial.

In one embodiment, before scanning a test object, a calibration blockand/or a separate section of the test object is scanned by theultrasonic transducer in a preliminary scan. The preliminary scan isused to generate a characteristic mother wavelet for the ultrasonictransducer. In subsequent scans by the ultrasonic transducer, thecharacteristic mother wavelet is based as the basis for wavelettransforms of the ultrasonic scan data. Utilizing a wavelet transformbased on the characteristic mother wavelet of the specific ultrasonictransducer, allows the system to more precisely detect deviations fromthe standard waveform of the specific ultrasonic transducer in order todetect defects in the test object.

3. Foreign Object Detection

One common issue with manufacturing composites is the remainder offoreign objects, such as portions of gloves, paper, tape, or otherobjects used during the manufacture of the composite. The presence ofsuch foreign objects in a composite facilitates the formation of crackswithin the composite, the propagation of which frequently causes partsto fail. Furthermore, the different material properties of the foreignobject contribute to decreased strength of the composite, also leadingto an increased chance of failure. In some cases, foreign objects arenot defects, but instead intentionally included inserts into thematerial, such as microarrays. In such cases, it is therefore useful formanufacturers to be able to ascertain whether the intentionally includedinserts have properly been included.

Current ultrasonic testing systems lack adequate resolution sizes todetect many of the most commonly sized foreign objects. Foreign objectscapable of causing issues within a test material are often as small as 1mm² with characteristic lengths as small as 1 mm, meaning that testingsystems require high precision in order to even report the presence ofthe objects, let alone precise and accurate data regarding the size ofthe objects. One study entitled “Improving Depth Resolution ofUltrasonic Phased Array Imaging to Inspect Aerospace CompositeStructures” by Mohammadkhani et al., which is hereby incorporated in itsentirety, tested a series of foreign objects made of several differentmaterials, each of which were square pieces having an area ofapproximately 36 mm². The study found that for a Teflon piece, anautomated method of detecting the size of the object overestimated by43.8%, while a manual method underestimated by 17%. Results with othermaterials were even further off, with the automated methodunderestimating the size of a peel ply defect by 66.7% and the manualmethod underestimating its size by 77%.

In one embodiment, the present invention is directed to a system able todetect foreign objects of sizes as small as 5 mm² and report the areasof the objects with an error lower than 10%. In another embodiment, thepresent invention is directed to a system able to detect foreign objectsof sizes of 1 mm² or greater and report the areas of the objects with anerror lower than 25%. In still another embodiment, the present inventionis directed to a system able to detect objects with diameters less than15 mm and report the diameters of the objects with an error of less thanhalf a millimeter. In yet another embodiment, the present invention isdirected to a system able to detect objects with diameters less than 5mm and report the diameters of the objects with an error of less than0.1 mm. In one study, Teflon pieces of four different sizes (denoted bydifferent letters) were placed at three different depths (denoted bydifferent numbers) each within a 12-lamina composite, with the firstdepth being between laminas 3 and 4 of the composite, the second depthbeing between laminas 6 and 7 of the composite, and the third depthbeing between laminas 9 and 10 of the composite. Those results are shownbelow in Tables 1 and 2.

TABLE 1 Teflon Object True Area vs. Detected Area Object True Area [mm²]Testing Area [mm²] Area Error [mm²] A1 126.71 133.25 6.54 A2 123.99127.63 3.64 A3 123.88 124.73 0.85 B1 28.87 30.63 1.76 B2 29.67 30.230.56 B3 29.13 28.43 0.70 C1 7.52 9.59 2.07 C2 7.67 8.01 0.34 C3 7.526.82 0.70 D1 1.81 1.82 0.01 D2 1.99 1.80 0.19 D3 1.81 1.34 0.47

TABLE 2 Teflon Object True Diameter vs. Detected Diameter True DiameterTesting Diameter Diameter Error Object [mm] [mm] [mm] A1 12.70 13.030.323 A2 12.56 12.75 0.183 A3 12.56 12.60 0.043 B1 6.06 6.24 0.182 B26.15 6.20 0.057 B3 6.09 6.02 0.073 C1 3.09 3.49 0.400 C2 3.13 3.19 0.068C3 3.09 2.95 0.148 D1 1.52 1.52 0.002 D2 1.59 1.51 0.081 D3 1.52 1.300.213 AVERAGE 0.148

FIG. 5 illustrates a group of graphical representations of a testmaterial provided by one embodiment of the present invention. As shownin FIG. 5, the GUI is capable of providing a single view with acorresponding A-scan image 102, B-scan images 104,106, C-scan image 108and a three-dimensional (3-D) layered image 110, constructed bycombining data from corresponding B-scan images 104, 106 and C-scanimages 108. The A-scan image 102 represents an average amplitude valuefor signals returning at a given time. In one embodiment, the A-scanimage 102 represents a weighted average amplitude, meaning that theamplitudes of the scans at particular positions in the object contributemore to the final A-scan image 102 than the amplitudes at otherpositions. As the values on the A-Scan image 102 represent averages, itis unlikely that the A-scan image 102 by itself would be able to showforeign objects or other defects in the test material unless the foreignobjects or other defects persisted across the entire cross section ofthe material. However, the difference in amplitudes over time in theA-scan image 102 is useful for characterizing different layers of thelaminate or large scale delaminations normal to the surface of the testmaterial within the material. A reference line 112 on the A-scan image102 indicates a depth within the test material, which is the same depthat which the C-scan image 108 displays a cross-sectional surface of alayer of the test material and is the depth at which the 3-D layeredimage 110 displays a cross-section of the test material.

The B-scan images 104,106 include a first B-scan image 104 showing thecross-section of the test material parallel to a first axis 114 and asecond B-scan image 106 showing the cross-section of the test materialparallel to a second axis 116, such that the first B-scan image 104 andthe second B-scan image 106 display cross-sections that are orthogonalto one another. The 3-D layered image 110 includes a top surface 118equivalent to the C-scan image 108, a first side surface 120 equivalentto the first B-scan image 104, and a second side surface 122 equivalentto the second B-scan image 106. In another embodiment, the systemautomatically generates a B-scan image of a foreign object and acorresponding depth from the surface of the test material for the B-scanimage.

As the ultrasonic testing device is performing the scan, the 3-D layeredimage 110 increases in depth until the testing is complete. In oneembodiment, after the testing has been completed, a user of the GUIselects a time point, which causes the GUI to display versions of theC-scan image 108 and the 3-D layered image 110 taken during the testingat the selected time point. In one embodiment, the time point isselectable by dragging the reference line 112 on the A-scan image 102.In another embodiment, the user selects the time point by entering in anumber value associated with the time point.

As shown in FIG. 6, in one embodiment, a foreign object 130 isrepresented as an area of color substantially different from the colorof the surrounding area. The foreign object 130 often presents itself asan area on one or more C-scan images 108 of the GUI, but in someinstances, presents itself on the B-scans images 104, 106, depending onwhere the foreign object is in the material. In another embodiment, theforeign object 130 does not appear as a different color and instead, the3-D layered image 110 is presented as a 3-D textured map, with theforeign object 130 being indicated as a recession or impression in thesurface of the image 110.

FIG. 7 illustrates a graphical representation of a foreign object in atest material provided by one embodiment of the present invention. FIG.7 provides a A-scan amplitude gradient map for a cross section of thetest material. By plotting the gradient of the A-scan amplitude for eachdepth of the material, a user is better able to visualize areas wherethere is a large shift in the acoustic impedance within the composite.These areas often correspond to foreign objects, as there is a strongacoustic impedance difference between the foreign object and thesurrounding composite material. In one embodiment, the GUI includes anediting tool enabling a user to hand trace an enclosed area of thecross-sectional gradient map. The system is then capable of providingdata regarding the area of the foreign object and the diameter of thematerial at specific X or Y coordinates of the cross-sectional gradientmap. In another embodiment, the system includes an artificialintelligence that automatically traces out the location of likelyforeign objects and provides information regarding area, characteristiclength, and/or center of mass of the object.

Foreign objects are distinguishable from air pockets or pores, which arefrequently caused by different defects such as cracks or delaminations,in the output data and graphical representations produced by the presentinvention. Because the difference in acoustic impedance between air anda composite material is very high, very few waves or waves of very lowamplitude are typically received and detected that travel to areaswithin the test material beyond an air pocket within the test material.Therefore, A-scans of regions with such defects frequently show a signalsimilar to the back wall of the material, namely a very sharp spike inamplitude followed by very little activity, at the point where airpocket causing defects are located. However, because foreign objectstypically have an acoustic impedance that is closer to that of theoverall laminate than air, such objects typically show a small A-scanspike and parts of the test material beyond the foreign object oftenstill return detectable signals. Therefore, the system is able todistinguish between the presence of foreign objects in the material andthe presence of air pockets caused by delaminations or cracks, which isuseful as the two different defects often have noticeably differenteffects on the properties of the overall test material. Moreover, in oneembodiment, the system includes a material database containing a list ofmaterials with acoustic impedance values for each material. If theproperties of a material match one of the materials listed in thematerial database, then the GUI will return a matching material or alist of potentially matching materials for the user.

In another embodiment, the system includes an artificial intelligence.The artificial intelligence is capable of identifying defects viaanalysis of the C-scan image 108, the B-scan images 104, 106, and/or the3-D layered image 110. In one embodiment, the defect identified by theartificial intelligence is a defect 130 visible in a cross-sectionalview provided by the C-scan image 108. In another embodiment, a defectis only visible between layers and can only be observed from the B-scanimages 104 and 106. In yet another embodiment, the artificialintelligence is capable of identifying defects in the test material thatare not easily identifiable by a user via the A-scan, B-scan, and C-scandata associated with the images provided by the GUI.

4. Bond Line Thickness

The integrity of an adhesive between two composite laminates or betweena composite laminate and an underlying substrate is key to maintainingdesired mechanical properties for the composite laminate. When the bondline thickness between two or more materials, which together form asingle combined material, is too thin, the failure load is reduced andso-called kissing bonds or complete disbonds can develop. Kissing bondsoccur where a small gap forms between the adhesive and one or more ofthe materials joined by the adhesive. The gaps formed in kissing bondsare small enough that they are not detectable by current systemsavailable on the market, meaning that while the adhesive appears to bein contact with an adjacent material in a scan, the materials areactually not mechanically and/or chemically coupled. Too large of adisbond between two materials causes premature failure, as the twomaterials separate entirely under certain loading conditions or causeweakening of the strength of the combined material by a shift of thefailure mode of the adhesively bonded structure.

Additionally, when the bond line thickness between two materials is toolarge, the combined material can suffer from an uneven distribution ofbond strength, which can cause load to be unevenly distributed andtherefore lead to premature failure of the part. Furthermore, uneventhickness along a bond line can cause issues where the combined materialperforms differently when loads are applied on different areas or atdifferent angles to the composite laminate, reducing the load carryingcapacity and making mechanical performance of the combined material moredifficult to accurately predict.

Another common issue with regard to the bond line of composite materialsis the presence of gaps, or void regions, in the bond line. These gaps,which often take the form of air bubbles, often are formed duringmanufacturing, when the adhesive is improperly spread before adheringtwo layers of a composite together. Even if the adhesive is properlyspread on the two layers, air pockets still often form when the twolayers are joined together. Furthermore, gaps also form during use dueto wear and tear of a part, as internal stresses build up within thecomposite. Existing hardware systems are limited in the size of gapsthat they are able to detect. Outside of an immersion tank, whereexisting systems commonly use phased array transducers or contacttransducers, the spatial resolutions of transducers are highly limitedby the spacing of the transducers within the array. Currently,transducer spacing for existing systems is between approximately 0.8 mmand approximately 1.5 mm, meaning that the theoretically smallest sizevoid region is approximately 1 mm, but, in practicality, the bestresolution is actually between 3 mm in width and 4 mm in width. Existingsystems are unable to achieve this theoretical resolution, as they needto utilize a plurality of ultrasonic transducers to generate sufficientpower to perform testing, which makes detecting and characterizingdefects on the order of 1 mm in width impossible, as there is anincrease in noise with the increase in number of transducers. Thepresent system is not limited in the manner existing phased array orcontact transducer systems, and, in one embodiment, utilizes aspherically focused transducer within a coupling fluid-filled portablehousing assembly capable of achieving a resolution approximately 10times greater than that of existing systems. As such, the present systemis operable to detect void regions having a width of less than 0.5 mm.Utilizing a single spherically-focused transducer within the couplingfluid-filled chamber allows the system to generate sufficient power toutilize only a single transducer during testing, as opposed to a bank oftransducers, meaning that the spatial resolution is increased.

Beyond simply the need to use more than one transducer, phased-arraysystems and flat front contact transducers suffer from other issues aswell. Because a flat front transducers do not highly focus the wavesthey emit to a single point on a test object, the flat front transducersreceive reflections back from a plurality of different spatial locationsin a single waveform. Because waves reflect back from the differentspatial locations at different types, noise is produced that makesdetermining the specific location or even the presence of smallerdefects difficult or impossible to perform based on the generated scandata. This is especially true for higher frequencies, which whileenabling detection of smaller defects, are more likely to cause the dataproduced by flat front transducers to be practically unusable,especially for larger parts. However, because the present system iscapable of utilizing a coupling fluid-filled chamber and thereforeutilize a spherically focused transducer, it is able to use higherfrequencies during testing, such as 15 MHz, while producing less noise,and therefore better detection capabilities, than a flat fronttransducer. Therefore, in one embodiment, the present system is able todetect void regions that extend through an area with thickness smallerthan 0.025 mm within the part.

Additionally, in situations where there is not adhesive at a portion ofa bond line, but two adjacent layers contact each other (with noadhesive) at that portion, the present system is operable to detect suchportions of the bond line. While areas where two adjacent layers are incontact necessarily do not have a detectable void before testing begins,as ultrasonic waves are emitted into the part, the two layers frequentlyvibrate such that separation is created between the layers that causes aphase shift of the reflected acoustic wave, which is observable in thereported scan data. Interestingly, this phenomenon allows the presentsystem, in some situations, to achieve through-thickness resolution anddetection capabilities that exceed even the limits of present ComputedTomography (CT) systems.

The present system is capable of achieving a higher resolution thanstandard techniques used in existing immersion-based scanning systems aswell. Existing immersion-based system techniques employ gating to obtaindata corresponding to specific depth ranges within a material and thencalculate the maximum amplitude within that range to determine if thereis a gap region. While this existing method is able to detect largervoids, it is inadequate for detecting smaller voids, which present aless obviously striking difference in amplitude when looking at alimited region of scan data. The present system, however, grabs theentire waveform of the ultrasonic waves emitted into a test object.Features that do not stand out within a limited gate region are oftenmore easily visible when viewed in the context of the entire waveform,meaning that the system achieves greater sensitivity than standardtechniques used in existing immersion systems.

The present system is operable to calculate a relative position of eachof one or more gap regions within a part. In one embodiment, therelative position includes a depth of each of the one or more gapregions. In another embodiment, the relative position includes a depthof each of the one or more gap regions in addition to a coordinate in aplane orthogonal to the direction of depth, allowing the system toreport at least one 3D coordinate corresponding to a location of each ofthe one or more gap regions. In yet another embodiment, the systemreports more than one coordinate associated with each of the one or moregap regions. Reporting more than one coordinate associated with each ofthe one or more gap regions allows the system, for example, to providecoordinates corresponding to the outer edges of the gap region, suchthat the precise size and shape of the gap region is able to berecorded.

Currently there is no known method of directly measuring spatialvariations in bond line thickness using ultrasonic techniques. It iscommon in the industry today to make use of manufactured calibrationwedges with known bond line thicknesses. By comparing signals receivedfrom a test material and those from the calibration wedge, techniciansattempt to approximate bond line thickness. However, this techniquerequires that calibration wedges be made for each material and has aprecision dependent on the number of calibration wedges used and thedifference between thicknesses of the calibration wedges.

FIG. 21 illustrates an A-scan image generating by one embodiment of thepresent invention. In one embodiment, the depth of a top surface of theadhesive layer at a first point is calculated by taking an A-scan 200for the first point and finding the final peak 205 before a sharp dropoff in amplitude, while the depth of a bottom surface of the adhesivelayer is defined as the next maximum intensity peak 210, as shown inFIG. 21.

FIG. 22 illustrates a first step in an algorithm used to calculate thedepth of an adhesive layer according to one embodiment of the presentinvention. In one embodiment, a series of A-scans are taken of the testmaterial at defined intervals along the axes X₁ and X₂. The A-scans aredivided into groupings, wherein each grouping consists of A-scanscovering approximately the same area of the test material. A series ofB-scans corresponding to different depths within a gated region aregenerated for an initial grouping 710, and the system calculates amaximum intensity value for each of the series of B-scans for each ofthe groupings. A series of B-scans are also generated for a plurality ofgroupings having the same X₁ value as the initial grouping 710 up to afinal X₁ grouping 712 and for a plurality of groupings having the sameX₂ value as the initial grouping 710 up to a final X₂ grouping 714. Foreach of the plurality of groupings having the same X₁ value as theinitial grouping 710 and for each of the plurality of groupings havingthe same X₂ value as the initial grouping 710, the system calculates amaximum intensity value for each of the series of B-scans.

As shown in FIG. 23, after calculating the maximum intensity values foreach of the series of B-scans, the system calculates the depth of thetop and bottom surfaces of the adhesive bond line for a point adjacentto two groupings for which the maximum intensity value was calculated.The maximum intensity value for the groupings adjacent to the pointserve as initial guesses, or seeds, in calculating the depths of the topand bottom surfaces of the adhesive layer at that point. The calculateddepths of the top and bottom surfaces of the adhesive layer at eachpoint serve as initial guesses, or seeds, for each subsequent adjacentpoint until the depths of the top and bottom surfaces for each point inthe scanned area of the test material are calculated.

As shown in FIG. 24, in one embodiment, the system is capable ofproducing a visualization 220, displaying constructed surfaces for botha top surface 225 and bottom surface 230 of the adhesive bond line. FIG.25 illustrates a visualization 228, displaying constructed surfaces fora top surface 235 and a bottom surface 240 of an adhesive bond line,wherein the bottom surface 240 is at an angle relative to the topsurface 235. FIG. 26 illustrate illustrates a visualization 238,displaying constructed surfaces for a top surface 245 and bottom surface250 of an adhesive bond line, wherein the bottom surface 250 has acomplex geometry relative to the top surface 245.

In another embodiment, a set of thickness values are generated in theform of an array of numbers for each point along the bond line, wherethe thickness value for each point is equal to the difference betweenthe depth of the top surface 225 and the bottom surface 230 at thatpoint. The GUI presents constructed surfaces for bond lines when boththe top surface 225 and bottom surface 230 are substantially parallel asin FIG. 24, as is commonly the case for bond lines between two straightcomponent materials of a combined material. In another embodiment, asshown in FIGS. 25 and 26, the top surface 235, 245 and bottom surface240, 250 are not substantially parallel. Evaluating situations where thetop surface 235, 245 and the bottom surface 240, 250 of the adhesivebond line are not substantially parallel is critical for the evaluationof combined materials with individual component materials that arecurved relative to one another, or for combined materials wherein thebond line has been substantially distorted.

In one embodiment, the visualization 220 of the top surface 225 and thebottom surface 230 is freely interactable by a user. For example, theuser is able to rotate the visualization 220 to show the bond line froma multiplicity of angles, which helps to identify areas of weakness orinconsistency that are not visible from a single angle. In anotherembodiment, the user is able to click on individual points of the topsurface 225 or the bottom surface 230, which will cause the system toprovide information regarding the bond line at the selected point,including the depth of the top surface 225, the depth of the bottomsurface 230, and/or the distance between the top surface 225 and thebottom surface 230 at the selected point, indicating the thickness ofthe bond line at the selected point. In still another embodiment, thesystem automatically calculates the curvature of the bond line and/orthe roughness of the interface of the bond line.

In one embodiment, a material used for the bond line of the testmaterial is matched to at least one material in a material database.Because the amplitude of the A-scan signal corresponding to the topsurface 225 and the bottom surface 230 of the bond line is based on thedegree of mismatch in the acoustic impedance of the composite materialand the bond line material, an approximate acoustic impedance of thebond line is able to be generated based on the amplitude of the A-scan.In another embodiment, a list of possible materials for the bond line isgenerated with a probability value assigned to each material. Producinga list is useful as materials often have similar acoustic impedances,meaning that it is feasible for the bond line to be made from severaldifferent materials. Furthermore, if the bond line is deeper within thetest material, the amplitude of the A-scan is less able to preciselydetermine what material the bond line is made from, as the amplitudewill have a greater margin of error. Therefore, it is useful to providethe user with several different possibilities for the content of thebond line, which, in some situations, would warrant furtherinvestigation.

As shown in FIG. 27, in one embodiment, the system is capable ofproviding a 2-D view of the adhesive bond line, with a color or huegradient indicating areas of greater or lower thickness. This view isparticularly useful not only for detecting areas at the extremity of thebond line where thickness is reduced or overthickened, but also forinterior regions of the adhesive bond line, wherein air pockets could befound due to manufacturing defects or due to fatigue. In anotherembodiment, the system displays areas of disbond, also referred to as anincomplete bond line, wherein there is a discontinuity between theadhesive layer and adjacent component materials, as white or anothercolor that sharply contrasts with the rest of the 2-D view of theadhesive bond line. In yet another embodiment, the 2-D view utilizesmeans other than color, such as the use of contour lines, in order todisplay regions of greater or lower thickness along the adhesive bondline. Discontinuities appear distinct in the waveform generated for thecomposite material. While a bond line is typically indicated by adistinct peak in the amplitude of one or more A-scans, corresponding tothe acoustic mismatch between the bond line and the adjacent layer ofthe test material, a full discontinuity within the piece appears as amuch stronger signal, due to the more substantial acoustic mismatchbetween air and the surrounding composite. In fact, this mismatch isoften so large that no signal is generated for points beyond thediscontinuity, while the system is still capable of receiving ultrasonicwaves and therefore generating signal data for areas of the materialbeyond the beginning of a bond line.

In another embodiment, the GUI provides a simplified view of thestrength of the bond line. The GUI first takes an input of the desiredbond line thickness of a given area of the material. The GUI thenpresents an image of a surface of the test material, with areas of thesurface of the test material associated with a plurality of colors,wherein each different color represents how close the bond line is to adesired bond line thickness. For example, in one embodiment, part of thesurface of the test material is colored green, indicating the bond lineis close to the desired thickness, part of the surface of the testmaterial is colored yellow, indicating the bond line thickness is closeto or just outside of the tolerance range for the desired bond linethickness, and part of the surface is red, indicating the bond linethickness is substantially different from the desired bond linethickness. In one embodiment, the user inputs tolerance ranges for eachof the plurality of colors, which indicates at what bond linethicknesses each color would appear. In another embodiment, the useronly inputs the desired bond line thickness with acceptable tolerancesand the system automatically calculates criteria for each of the otherplurality of colors. In one embodiment, the plurality of colors onlyincludes two colors, for situations in which a binary decision is usefulor necessary. In another embodiment, the plurality of colors includesmore than two colors and the user is able to select how many differentcolors appear.

5. Barely Visible Impact Damage

One frequent issue with composite laminates occurs when the composite issubjected to high or low velocity impacts during manufacturing oroperation. Such impacts often cause cracks, delamination, fiberbreakage, or penetration of the composite. In many cases, impact damageseemingly only causes a small, sometimes undiscernible surface defect onthe material, while the internal damage can be far greater.

Existing systems have been unable to full characterize defects caused bysuch impact damage. Impact damage poses a particular issue, ascomplications such as undesired reflections, wave interactions,refraction, and diffraction has rendered areas near the surface of acomposite an imaging “dead zone,” making current ultrasonic imaging ofsuch areas highly unreliable with low resolution. One recent study byZhang et al. attempted to use an ultrasonic pitch-catch procedure tofind barely visible impact damage for a composite. However, while themethod was able to detect the existence of the damage, it was unable toquantify size, shape, or location of the damage, greatly limiting theusefulness of the result in the field.

Other existing techniques, such as 3-D microscopy have a tendency tosubstantially underestimate the size of damage, especially for areas ofa test material close to the surface. Furthermore, 3-D microscopy cannotbe used to precisely measure internal damage in the test materialwithout damaging part of the test material. In fact, the differencebetween area of surface damage and the cross-sectional area of thelargest area of damage within the material can often be substantial.Table 3 demonstrates the percentage difference between the area ofsurface damage of a material, as found by 3-D microscopy, and themaximum cross-sectional area of damage within the same material foundusing a portable ultrasonic transducer according to one embodiment ofthe present invention.

TABLE 3 Percent Difference in Area Between Surface damage and MaximumDamaged Area Found Using Portable Ultrasonic Transducer Sample 1 Sample2 Sample 3 Sample 4 Value MGA FSI MGA FSI MGA FSI MGA FSI Difference (%)170 171 149 149 149 149 152 152

Characterizing the actual size and shape of the damaged area caused byan impact is critical in being able to evaluate the effect of thedamaged region on the overall mechanical properties of the material. Inone study, Finite Element Analysis (FEA) revealed that simulationsinvolving a part whose damage was assumed to be perfectly cylindricalwith the same radius as the impact hole significantly underestimated theincrease in von Mises stress in the material compared to simulationssimulating the actual damage area caused by the impact. Table 4 belowshows the percent increase in maximum von Mises stress calculated by anFEA model for three different sample material, for simulation bothassuming perfectly cylindrical damage and simulations taking intoaccount the actual damage area.

TABLE 4 Von Mises Stress Increase - Perfectly Cylindrical vs. ActualDamage Area 10% Stiffness 10% Stiffness 90% Stiffness 90% StiffnessReduction − Reduction − Reduction − Reduction − Specimen CylindricalCylindrical (% Actual (% Cylindrical (% Actual (% Number Radius (mm)increase) increase) increase) increase) Specimen 2 2.94 4.95 9.6 140 320Specimen 3 3.16 4.96 7.5 140 220 Specimen 4 3.20 4.96 9.1 140 290

In one embodiment, an initial thermographic scan is taken of a testmaterial using a thermographic testing apparatus. The initialthermographic scan is used to identify an area of potential damage onthe test material. Taking an initial thermographic scan is usefulparticularly for larger parts, such as airplane wings, as performingultrasonic scans of the entire wing is frequently very expensive andtime consuming, especially when only limited areas of the part areexposed to damage. Additionally, identifying areas with barely visibleimpact damage with the naked eye is difficult, as the surface defectspresent at those areas are, by their nature, barely visible, potentiallyeven microscopic and invisible to the naked eye. Because the system doesnot rely on the presence of surface damage in order to quantify theinterior damage, the system is able to determine damage area even wherethere is no surface damage at all.

In another embodiment, a phased array ultrasonic testing apparatus isused to scan the area of potential damage after the initialthermographic scan is performed. The phased array ultrasonic scan isused to identify likely areas of damage to be investigated further.Performing a subsequent sweep with a phased array ultrasonic testingapparatus is useful, as the initial thermographic scan often lackssufficient specificity or accuracy as to fully narrow down an area ofthe test material that is more practical for individual testing.

In yet another embodiment, an initial thermographic scan is notperformed on the test material and only the phased array ultrasonictesting apparatus and an individual scan transducer are used to scan thetest material. In still another embodiment, neither an initialthermographic scan nor a phased array ultrasonic testing apparatus isused and only an individual scan transducer is used to scan the testmaterial.

In one embodiment, the system includes a scan of an area surrounding asurface impact. A transducer emits ultrasonic waves to produce an A-scanof the region, after which a gate is selected for the A-scan, withdefined a defined gate start time and gate end time, defining a seriesof gate time points therebetween. The first gate time point correspondsto a cross section of the test material closest to the surface of thetest material, while the final gate time point corresponds to a crosssection of the test material furthest from the surface of the testmaterial. In one embodiment, the gate is chosen based on the averagethickness of a single lamina of the test material. In anotherembodiment, the average thickness of a single lamina of the testmaterial is found automatically by the test, based on A-scan dataindicating the number of laminae in the test material and the total timeof flight between the first and final lamina of the material.

The maximum value for every A-scan in the region for each gate timepoint is then plotted to produce a series of C-scans from the maximum ofthe absolute value of the gated A-scan (or MGA C-scans) for each gatetime point at each point in the region. In one embodiment, a Fouriertransform is performed for the gated data, utilizing a low pass filterof 15 Mhz, with numerical integration of the absolute value of thespectrum produced. This filtered data is then plotted to produce aseries of frequency spectrum intensity (FSI) C-scans. A damage area isthen determined for each of the MGA C-scans and the FSI C-scans. In oneembodiment, the damage area is determined manually by an operator. Inanother embodiment, the damage area is determined automatically by aprocessor. Each C-scan of the series of MGA C-scans and FSI C-scans arethen compared by the system. The system creates a series of reconciledC-scans, wherein each C-scan in the series of reconciled C-scans is thesame as the C-scan of either the series of MGA C-scans or the series ofFSI C-scans, depending on which has the largest damage area for a givengate time point. Using both MGA and FSI C-scans is useful, as MGAC-scans on average tend to estimate the damage area as being larger thanthat shown in FSI C-scans and therefore is the more conservativeapproach overall. However, FSI C-scans are often better able to resolvesmall damage areas and therefore are useful in obtaining a clearerpicture of the overall change in the properties of the test material.

In one embodiment, as shown in FIG. 28, the system is operable to createa visualization 310 of the damage area of each C-scan in the series ofMGA C-scans and a visualization 320 of the damage area of each C-scan inthe series of FSI C-scans. The damage area 332 corresponding to thefirst gate time point is at the top of each visualization 310, 320,while the damage area 334 corresponding to the final gate time point isat the bottom of each visualization 310, 320. The system is operable tocreate a 3-D damage profile for the region consisting of the damage areaof each C-scan in the series of reconciled C-scans stacked vertically,with the damage area 332 corresponding to the first gate time pointbeing at the top and the damage area 334 corresponding the final gatetime point being at the bottom. In one embodiment, the centroids of eachdamage area are automatically vertically aligned by the system. In oneembodiment, the system creates a visualization 340 of the damage area ofeach C-scan in the series of MGA C-scans and a visualization 350 of thedamage area of each C-scan in the series of FSI C-scans for a testmaterial where there is no visible surface damage, as shown in FIG. 29.The damage area 352 corresponding to the first gate time point is at thetop of each visualization 340, 350, while the damage area 354corresponding to the final gate time point is at the bottom of eachvisualization 340, 350.

In one embodiment, as shown in FIG. 30, the system uses FEA to develop avon Mises stress profile displays this graphically for all or part ofthe test material. The von Mises stress profile assists in associatingthe damage area associated with the impact with a quantifiable decreasein the performance of the part in question.

6. Wrinkle Detection

Another defect that has the potential to impact the mechanicalproperties of a composite laminate is a wrinkle or waviness between thelayers of the composite. Wrinkles between layers of the compositefrequently occur during manufacturing, when the composite is not fullyset and is more amorphous, especially for pieces with complex curves.For thin parts or for parts where wrinkles are quite large, theseabnormalities are often spotted early through a simple visual analysisof the surface of the part. However, for thicker composites, especiallywhere the wrinkle is small relative to the thickness of the part andwhere the wrinkle is in a layer distant from the surface of the part,visual analysis may not reveal an issue, as the part will appear to besmooth on its surface.

When a composite having wrinkles is put into tension, the wrinkled layeris frequently not taut like each of the other layers, meaning it is notengaged in tension and does not contribute to the overall strength ofthe composite laminate. Additionally, when a composite is placed incompression, the wrinkle is able to buckle instead of engaging the load,leading to a noticeable decrease in the compressive strength of thecomposite. This frequently causes the composite to fail prematurely. Inorder to be able to detect the majority of wrinkles big enough tosignificantly impact the performance of a composite, ultrasonic testingsystems need to be able to at least detect wrinkles with an amplitude of0.4 mm or larger. Current ultrasonic systems are unable to achieve thisresolution and therefore are highly likely to miss important defects ina composite. In addition to the size of the wrinkles, of criticalimportance in evaluating the potential danger of a wrinkle is its aspectratio. The aspect ratio of a wrinkle is defined as the amplitude of thewrinkle divided by the half wavelength. Wrinkles with low aspect ratiosare more difficult to detect because at longer length scales, they oftenappear to be flat relative to adjacent layers. Therefore, systems beingable to detect wrinkles with low aspect ratios is often as critical asbeing able to detect wrinkles with low amplitudes.

The present system is operable to detect and characterize wrinkles inboth unidirectional and woven composites. Additionally, the presentinvention is able to characterize wrinkles in a variety of materials,including, but not limited to, carbon fiber composites, fiberglasscomposites, and glass-carbon composites. The present system is able toresolve images of wrinkles having amplitudes of approximately 0.05 mm orlarger in unidirectional composites. In woven composites, due to thelarger size of the plies themselves, the system is able to resolveimages of wrinkles having amplitudes of approximately 0.2 mm or larger.In one embodiment, the system is able to detect wrinkles having aspectratios of 0.1 or greater.

In one embodiment, the system is able to find Marcel wrinklespropagating within a plane normal to a testing surface of a test object.In most situations, wrinkles are identified as existing between laminaof a test object, with one lamina pushing up into another and viceversa. However, in some situations, such as where the wing of a planecontacts the fuselage of the plane, the wrinkles do not only propagatebetween the lamina, but rather within individual lamina.

As shown in FIG. 31, in one embodiment, the system produces a series ofB-scans 140 of a test material that show a series of cross sections ofthe test material spanning the entire width of a woven material. Inanother embodiment, the user is able to select a start gate time and anend gate time so as to only produce a series of B-scans of the testmaterial for a limited range of depths of the test material.Additionally, the user is able to select a start distance, indicating atwhat distance from the surface of the test object the first B-scan showsand an end distance, indicating at what distance from the surface of thetest object the final B-scan shows. By showing a series of B-scans 140through the thickness of the test material, an operator is able to seeareas where the relative position of two layers of the material differthrough the width of the test material, which commonly indicates thepresence of a wrinkle 142 in the test material. In one embodiment, anartificial intelligence system automatically detects wrinkle areas fromthe series of B-scans and highlights the problem areas for the user. Inanother embodiment, the system automatically determines at what depthfrom a surface of the test material that the amplitude of the wrinkle142 exceeds a predetermined threshold and at what distance from theoutside surface of the test material that the amplitude of the wrinkle142 falls below the predetermined threshold for each layer of thecomposite. By detecting where the wrinkle ends within each layer withinthe composite, the complex geometry of the wrinkle, rather than simplyits height at a given cross-section, is provided. As shown in FIG. 32,in one embodiment, the system provides a two-dimensional view of thetest material with the wrinkle area traced. Additionally, in oneembodiment, the system is capable of providing graphics showinginformation related to the wrinkle, such as the height of the wrinkle,the depth of the wrinkle, the length of the wrinkle, and/or the aspectratio of the wrinkle.

FIGS. 33 and 34 illustrates a three-dimensional graphical representation144 of a wrinkle 142, 146 in a test material provided by one embodimentof the present invention. In addition to providing a cross section of atest material, the present system is further able to produce a 3-Drepresentation 144 of an individual layer of a test material, includingvariations in the depth of the layer indicating curvature of the layeror a wrinkle 142, 146 in the layer. After the system compiles A-scandata for a series of cross-sections of a test material to produce aseries of C-scans, the system is able to perform gradient analysis onthe series of C-scans in order to construct a series of X, Y, and Zcoordinates corresponding to the interface between two layers. Thesystem is then able to plot these coordinates in a 3-D graphicalrepresentation 144, indicating the dimensions of width, length, anddepth of the test material. In one embodiment, the system furtherassigns coloration to sections of the 3-D graphical representation 144,with different colors corresponding to different depths of the layer. Inanother embodiment, the system includes a graphical editing module, withwhich users manually map out the interface or part of the interface,which creates a series of X, Y, and Z coordinates that are then plotted.

As shown in in FIG. 35, in one embodiment, the system is able toautomatically isolate the wrinkle 146 from the surrounding testmaterial. In one embodiment, the wrinkle is isolated by finding thelocal curvature at each point along the lamina and finding points alongthe surface where the curvature of the surface extends a predeterminedthreshold. In another embodiment, a portion of the surface of the laminais able to be manually selected and excised to be shown independently ofthe non-selected portion of the lamina. As shown in FIG. 36, in anotherembodiment, the system is able to display a 2-D top view of the wrinkle146. In one embodiment, the 2-D top view of the wrinkle uses colorationto denote the relative depth and/or height of different sections of thedisplayed lamina.

7. Porosity Determination

The porosity of a material has substantial effects on the mechanicalproperties of that material. Pores are small holes in a material,commonly filled with air. Increased number of size of pores within amaterial frequently causes materials to show decreased strength, whichoccasionally lead to premature failure.

In order to evaluate the porosity of a material, current ultrasonicsystems utilize calibration blocks of materials with known porosity,which are first measured by the device in through-transmission mode. Inevaluating the amplitude and timing of the ultrasonic signals capturedby a receiver on the opposite side of the calibration block to thetransducer, current systems are able to develop baseline measurementswith which to compare the test material. However, these current systemsface several key issues. Calibration blocks often need to be uniquelyformed for individual test materials depending what material is to betested and the geometry of the material to be tested. For partiesseeking to measure the porosity of many different objects, calibrationblocks often become expensive and time consuming to produce.Additionally, relying on the use of calibration blocks limits theaccuracy of a system, as the system is only able to determine thecalibration block that the test material most closely matches, whichlimits accuracy to depend on the minimum difference in porosity betweencalibration blocks.

Furthermore, these systems frequently rely on through-transmission modesin order to operate. However, through-transmission ultrasonic testingoften cannot be performed, as the user is unable to access a second sideof the test material or the test material is too thick for throughtransmission techniques to work reliably. However, for situations whereonly a single surface of a test material is available, currentultrasonic systems lack sufficient resolution to evaluate the porosityof the sample in pulse echo mode.

In one embodiment, the system determines the porosity of a testmaterial. The system is able to directly and quantifiably measure theoverall average porosity of a test material, without the need to compareto a calibration block. In another embodiment, the system providesstatistical information regarding the average size of pores, such as thestandard deviation and variance of the pore size. In one embodiment, thesystem is able to determine the overall average porosity of a testmaterial while in pulse echo mode. In one embodiment, the system is ableto determine an overall void percentage for a test material, includingcarbon fiber and/or fiberglass, as low as 2%.

In addition to determining the overall average porosity of a testmaterial, it is also critical to indicate the size and location ofoutlier pores, as conveying overall average porosity alone ispotentially misleading if the average is significantly affected by alarge void in the material. These outlier pores frequently serve asinitiation points for crack formation or help to facilitate thepropagation of existing cracks in the test material. However, existingsystems lack sufficient spatial resolution to detect and report manypotentially disqualifying pores, especially in deeper areas of amulti-layered composite, where spatial resolution decreases. Therefore,in addition to conveying the overall average porosity of the material,the system is able to detect and identify individual pores with sizes of1.5 mm or greater within any layer of a composite having up to 18 totallayers.

In one embodiment, the system B-scan, C-scan and/or three-dimensionalimages of the test material containing an outlier pore. The systemindicates the pore using a visible outline, shading, or any other visualindication method. The system is able to automatically provide theeffective diameter, area, and depth of the pore. In one embodiment, thesystem automatically fits an ellipse around the pore in order to modelit and reports the dimensions of the major and minor axis of the ellipsein order to provide better information regarding its shape.

8. Degree of Cure Evaluation

Another frequent defect in a test material is improper curing of thetest object and/or improper curing of the adhesive used to bindindividual layers of the test object. Composite laminates are oftenformed by first providing a series of prepreg sheets of a woven basematerial, such as carbon fiber or fiberglass. The prepreg sheets areimpregnated with a resin, such as epoxy, polyester, polyurethane, vinylester resin, or another plastic, within a controlled thermal environment(e.g. a furnace) until the resin within the prepreg cures forming asingle solid plastic part. In other instances, parts are able to bemanufactured without the use of prepreg sheets using a dry infusionprocess. Furthermore, in some instances, parts are manufactured andcured without the use of a controlled thermal environment in “open air”environments. Unlike in a controlled thermal environment, in an open-airenvironment, temperature and pressure are often not readily alterable.Therefore, in an open-air environment, controlling the amount of timethe part is allowed to cure is critical for properly curing the part.

Determining the temperature, pressure, and/or duration of the curingprocess is often essential for obtaining a suitable part. Altering thetemperature at which the polymers are cured or the duration of thecuring affects the degree to which chain-growth polymerization is ableto occur and the density of cross-linking within the polymer. Producingpolymers with very high degrees of cross-linking contributes to higherultimate stresses in the polymer, while also making it more brittle. Onthe other hand, allowing more chain-growth polymerization to occur,while less cross-linking occurs contributes to increased ductility, butis likely decrease the ultimate strength of the polymer. Therefore,regulating the conditions under the polymer forms is critical toregulating the properties of the polymer.

While methods (e.g. thermographic analysis) exist to evaluate the degreeof cure of parts after the curing process is complete, there currentlyexists no method to non-destructively analyze the curing process in-situduring fabrication. Furthermore, thermographic analysis is unable to beused for thin parts, as the heat of surrounding elements around the partare picked up by the infrared camera, often leading to misleadingcharacterizations of the cure state of the part. Real-time ultrasonicmonitoring and/or scanning of parts is therefore advantageous, as itallows the curing process to be adjusted in real-time, obviating theneed for timely and often wasteful “guess and check” type feedbackloops.

Some parts are not subject to a controlled thermal and/or pressureenvironment, and therefore the duration of their curing is most criticalin determining whether the part is suitable. For manufacturing processesoutside a controllable environment, temperature, humidity, and pressureoften vary greatly over the course of a day, let alone a longer timeperiod. As such, one part could be properly cured after, for example, 7hours, while an identical part is properly cured after 8 hours,depending on the temperature and pressure fluctuations whilemanufacturing. Right now, manufacturers choose a common amount of timefor each part and accept lower finesse in the curing process, butallowing the part to be analyzed in real-time would allow for each partto be nearly optimally cooled. For other processes, providing a feedbackcontrol loop initiated to adjust thermal and pressure loadings wouldhelp to achieve the desired cure state. Additionally, some curingprocesses occur over very short time scales (e.g. less than 10 minutes).In order to ensure proper curing, many of these processes use highlycontrolled environments and test multiple parts in order to determinethe optimal curing parameters. With the present system, curing processesare able to be optimized in real-time, meaning that fewer parts need togo to waste in order to refine the curing process.

Depending on the method of manufacturing used to produce a part,critical parameters for determining whether a part is properly curedinclude the temperature at which the part is kept during and/or aftermanufacturing, the pressure at which the part is kept during and/orafter manufacturing, and the time taken to perform the curing process.Exposing a part to a higher temperature, for example, causes thematerial to become more cured and therefore grow stiffer and morebrittle, which may or may not be desirable depending on the part. On theother hand, exposing a part to a lower temperature, for example, causesthe material to be less cure, making it less strong than a more curedmaterial, which may or may not be desirable depending on the part.Therefore, a system is needed that is able to evaluate both if a testobject is properly or improperly cured.

In one embodiment, an ultrasonic emitter probe is inserted into acontrolled thermal environment during the curing process. The ultrasonicemitter probe emits ultrasonic waves into the test object duringheating. Waves reflected by the material are captured by an ultrasonicreceiver probe and processed by the system to produce data concerningthe degree of cure over the duration of the curing process. Degree ofcure is evaluated by the degree of attenuation in the data received bythe ultrasonic receiver probe coupled with the signal centroid, whilestiffness is also evaluated using signal centroid and energy analysis.By finding both the degree of cure of the material and the stiffness ofthe material, the strength of the material is also able to be determinedfor a given polymeric system. In one embodiment, the ultrasonic emitterprobe and the ultrasonic receiver probe are the same device. In oneembodiment, the system is in communication with a control unit for thecontrolled thermal environment, and the heat and/or timing of thecontrolled thermal environment used for the curing process isautomatically adjusted based on the data produced while the curingprocess is ongoing. In another embodiment, the system is in connectionwith a control unit for the curing tool, and the heat and/or timing ofthe curing tool used for the curing process is automatically adjustedbased on the data produced while the curing process is ongoing.

In another embodiment, an ultrasonic emitter probe is placed outside ofthe controlled thermal environment and emits ultrasonic waves into thetest object shortly after the curing process is complete. The systemproduces data regarding the degree of cure of the test material based onthe reflected ultrasonic waves. In one embodiment, the system isconnected to a heat control unit for the controlled thermal environmentand the data is used to automatically adjust the temperature, pressure,and/or duration for subsequent curing iterations. In another embodiment,a user manually updates the heat control unit for the controlled thermalenvironment based on the data produced by the system.

The present invention is capable of examining parts undergoing a curingprocess using both continuous scanning and by monitoring at specificpoints on the part. In one embodiment, as shown in FIG. 37, the part 405undergoing the curing is positioned on a tool 410. The tool 410 has atleast one acoustic window 415, which is a section of the tool 410 madeof a material more closely matching the material properties of the resinbeing examined, rather than the aluminum or other metal that typicallyconstitutes a tool 410. Utilizing an acoustic window 415 helps toseparate the tool 410 from the part 405 during analysis, as the acousticwindow 415 is likely to propagate waves slower than a metal substrate. Atransducer 420 is positioned adjacent to the at least one acousticwindow 415 in order to continuously monitor the part 405 at thatposition. In one embodiment, the part 405 is covered with baggingmaterial 425. In one embodiment, the transducer 420 is connected via acable 430 to a pulser receiver. In one embodiment, the transducer 420 isa contact transducer, coupled to the acoustic window 415 via an acousticgel 435. In another embodiment, the transducer is part of a portabletransducer housing with an interior coupling fluid (e.g. water) chamber.For larger parts, utilizing more than one acoustic window and more thanone transducer is advantageous, as the larger surface area decreases thelikelihood that the degree of cure will be the same at all points in thepart.

In a scanning embodiment, one or more transducers are used tocontinuously scan a substantial portion of or all of the part. Ratherthan monitor at one or more specific locations on the part, the scanningembodiment examines the entirety of the part in real time. By scanningsubstantially all of the part, there is no reliance on the principlethat the majority of the part will be at approximately the same degreeof cure, meaning that decisions regarding the curing process are able tobe more accurately fine-tuned.

In one embodiment, when the ultrasonic waves are transmitted into thetest object, some waves reflect off the boundaries between adhesivelayers and adjacent solid layers, while other waves reflect off of abagging material surrounding the test object. Based on the amplitude ofthe returned average A-scan collected from the test object, the test isable to determine whether each adhesive layer is properly cured. This isdirectly contradictory to other existing methods of evaluating the cureof an adhesive, such as that found in U.S. Pat. No. 6,945,111, whichrequires that a probe be in solid contact with an adhesive regiondirectly and only reflect off a backing material in order to gain aclear enough amplitude to distinguish between properly and improperlycured states for an adhesive. It should also be noted that unlikemethods such as that described in U.S. Pat. No. 6,945,111, the presentsystem determines the cure state of a resin within the layers of acomposite and/or the cure state of an adhesive between adjacent layersof the composite, and not the cure state of an adhesive within thehoneycomb pattern within a composite. In fact, existing methods arelimited by the highly specific set-up required in order to evaluate thecure of composite, meaning that the testing equipment used for suchmanufacturing systems is generally incapable of being adapted to otherdevices.

Additionally, the system of the present invention is capable ofevaluating the degree of cure of the composite using a liquid coupledtransducer, specifically the portable transducer housing systemdescribed herein. Existing systems avoid using liquid couplant in orderto evaluate the degree of cure of a test object because the liquidcouplant more easily evaporates or damages the curing process whenplaced into direct contact with the test object during the manufacturingprocess. Because of this, existing systems typically make use ofentirely solid-coupling, air coupling, or contact transducers will smallamounts of acoustic gel between the transducer and the test object.However, each of these methods is highly limited in its resolutioncompared to, for example, a water-coupled spherically focusedtransducer. Furthermore, using spherically focused transducers allowsfor higher frequency, higher energy images, which provide higher qualitydata for the part. Therefore, the present system allows higherfrequencies accommodating an increased accuracy in testing for thedegree of cure of a test object, especially when testing for the degreeof cure of multiple layers of the test object simultaneously.

In one embodiment, the system is operable to produce a 3D graphicalimage of the test object after the scan is complete. In one embodiment,the 3D graphical image includes color coding, indicating less highlycured areas as, for example, blue, more highly cured areas as, forexample, red, and intermediately cured areas as, for example, green. Itshould be noted that any coloration scheme is able to be used for the 3Dgraphical image and other indications of the degree of cure are alsoable to be used, such as differential shading.

In one embodiment, differential scanning calorimetry (DSC) is used onsamples of the resin for individual polymers in order to determine thecorrelation of degree of cure with the ultrasonic A-scan results for thematerial. By performing DSC on a given material, the system is able toalign this data with that obtained from the transducer in order toprovide real-time evaluation of the degree of cure of the material. Inone embodiment, the system includes a database of polymers, each withtheir own DSC determined cure profiles.

9. Layer Orientation

As discussed in U.S. Pat. No. 10,697,941, which is hereby incorporatedby reference, test materials, such as composite laminates, are oftencomposed of individual layers that have directionally dependent materialproperties. For example, based on whether the fibers are unidirectionalor a 2D weave within an individual lamina and based on the orientationof the fiber tow within that lamina, the material will often havedifferent properties (e.g. tensile strength, compressive strength,thermal conductivity, electrical conductivity) along differentdirections within the lamina.

Currently, the majority of ultrasonic testing systems and processes areincapable of determining the ply orientation of each lamina of a testmaterial. Instead, several studies have proposed the use of computedtomography (CT) imaging in order to determine ply orientation. However,CT scans require high initial investment costs and are impractical to beused on large parts.

In one embodiment, the system is able to determine the relativeorientations of the fiber tow within each individual layer of thecomposite. A series of A-scans are generated for a region of a testmaterial. For each of the series of A-scans, a plurality of gates areselected. The plurality of gates are chosen to be smaller than anindividual lamina of the test material, often as small as 1/10 thethickness of a lamina of the test material. For each of the plurality ofgates, a C-scan is generated from the amplitude data for each of theA-scans at a given gate. A user is able to view smoothed C-scan data,such as the C-scans shown in FIGS. 38 and 39. In one embodiment, atwo-dimensional (2-D) Fast Fourier Transform (FFT) is applied to theC-scan data to produce clearer C-scan representations, such as thoseshown in FIGS. 40 and 41. As illustrated in FIG. 40, fibers 402 with azero-degree orientation relative to a reference line are clearlyidentifiable. As illustrated in FIG. 41, fibers 404 with anon-zero-degree orientation relative to a reference line are alsoclearly identifiable. In another embodiment, the system then uses aRadon transforms, wavelet transform, Hough transforms, Eigensystemanalysis, and/or other data transforms to determine the principal fiberdirections utilizing the C-scans. Transformation of the C-scan dataallows a user to individually determine the thickness of each ply ineach layer of the material, in addition to determining the orientationof the fiber tow in each generated C-scan relative to adjacent C-scandata. In one embodiment, values for the average ply thickness andorientations of the fiber tow in each generated C-scan is automaticallygenerated. In one embodiment, obtaining the thickness of each layer ofthe composite involves a first calibration step, in which the speed ofsound of the material is obtained. In another embodiment, if the overallthickness of the test object is known, no first calibration step isrequired. When the speed of sound is known or the overall thickness ofthe material is known, an average A-scan 102, such as that shown in FIG.19, provides sufficient information in order to obtain the number ofthickness of the layers. Notably, the method of the present invention isable to find the fiber orientation for composites with a 2D wovenlaminae, which existing methods are unable to provide.

The use of a 2D FFT on the C-scan data is able to provide demonstrablebenefits over the use of other transforms, such as a Radon transform.For example, other transforms often show peaks from multiple differentadjacent lamina of a composite, meaning that the fiber orientations ofeach individual layer frequently become confused. Furthermore, the useof a 2D FFT is computationally simpler than many other transforms,reducing the time and memory required by computers to completeprocessing. Unexpectedly, a 2D FFT also allows for higher precisionregarding the angle of each individual lamina, due to having highersensitivity to subtle changes in fiber orientation.

In another embodiment, the system is also able to determine otherproperties regarding the layering of the composite, including the numberof layers, thickness of each layer, weave type of the fibers of eachlayer, and/or the total thickness of the sample.

10. Curved Parts

One common issue encountered in non-destructive testing is when testobjects do not have a planar surface. Some test objects have positive ornegative curvature in one direction, but zero curvature in a seconddirection (e.g. the barrel of a cylinder). Other test objects havepositive or negative curvature in more than one direction (e.g. asphere). Curved parts pose several challenges to ultrasonic scanning.First, curved parts often have different thicknesses and/or otherproperties at different points on the part. Therefore, simply testingthe part at discrete locations using a contact transducer is incapableof fully and adequately characterizing the part. Frequently, thethickness of curved parts change along the length of a part, as one ormore plies drop from one area of the part to the next area of the part.Outside of an immersion tank, current ultrasonic testing systems lackthe necessary precision in order to detect this ply drop along thelength of the part.

Furthermore, the systems most commonly used to scan over an area of apart are phased-array systems. However, phased-array systems requirethat the array has transducers pointed in a direction normal to thesurface of the part in order to properly obtain data. This especiallyposes an issue for parts that curvature in more than one direction, asthe phased array device would need to be specifically designed toconform to the curvature of the part, which would often be prohibitivelyexpensive and time consuming. Furthermore, even if the phased arraydevice were designed to match the curvature of a part at a specificpoint, parts with more complex curvatures (e.g. curvature that changesalong the length of the part) would still not be scannable by the phasedarray system.

The present system is capable of scanning curved parts in or out of animmersion tank with high precision. Because only a single transducer isneeded for the present system, there is no issue of needing to redesigna new phased-array system for each part. Furthermore, while phased arraysystems require high precision to match the curvature of the part, thepresent system has higher tolerance, allowing the transducer toeffectively scan the part, as long as the transducer is normal to thesurface of the part or less than 7 degrees off normal. In oneembodiment, the main transducer used to scan a part with a non-planarsurface is paired with an offset transducer. The offset transducer emitsand receives ultrasonic waves in order to determine how far off the maintransducer is pointed relative to an axis normal to the surface of thepart at a specific point. The system then adjusts the angle at which themain transducer scans the next point along the part based on the datareceived from the offset transducer. In another embodiment, tap testingis used to determine the relative orientation of the surface of the partat a given point in order to adjust the positioning of the maintransducer. In yet another embodiment, flash thermography is used todetermine the relative orientation of the surface of the part at a givenpoint in order to adjust the positioning of the main transducer.

Because the main transducer used in the system is able to operate at ahigh frequency, between 5 MHz and 15 MHz, it is capable of achieving adegree of precision not possible to achieve in current contacttransducer systems. Therefore, unlike current contact transducers, thepresent system is capable of scanning the whole part, with high enoughprecision to detect ply drops along the length of the part. In oneembodiment, the system is operable to generate a set of valuescorresponding to the depth and thickness of a specific layer (e.g. anadhesive bond layer) of a part with a nonplanar surface. In oneembodiment, the system is operable to provide the number of plies ateach location on the part. In one embodiment, the system is operable toproduce a 3D graphic of the part, including providing thickness valuesof the whole part and/or one or more individual layers of the part ateach point along the part. In one embodiment, the thickness of the partalong each point is indicated by color coding of the surface of the partat that point.

FIG. 42 is a schematic diagram of an embodiment of the inventionillustrating a computer system, generally described as 800, having anetwork 810, a plurality of computing devices 820, 830, 840, a server850, and a database 870.

The server 850 is constructed, configured, and coupled to enablecommunication over a network 810 with a plurality of computing devices820, 830, 840. The server 850 includes a processing unit 851 with anoperating system 852. The operating system 852 enables the server 850 tocommunicate through network 810 with the remote, distributed userdevices. Database 870 is operable to house an operating system 872,memory 874, and programs 876.

In one embodiment of the invention, the system 800 includes a network810 for distributed communication via a wireless communication antenna812 and processing by at least one mobile communication computing device830. Alternatively, wireless and wired communication and connectivitybetween devices and components described herein include wireless networkcommunication such as WI-FI, WORLDWIDE INTEROPERABILITY FOR MICROWAVEACCESS (WIMAX), Radio Frequency (RF) communication including RFidentification (RFID), NEAR FIELD COMMUNICATION (NFC), BLUETOOTHincluding BLUETOOTH LOW ENERGY (BLE), ZIGBEE, Infrared (IR)communication, cellular communication, satellite communication,Universal Serial Bus (USB), Ethernet communications, communication viafiber-optic cables, coaxial cables, twisted pair cables, and/or anyother type of wireless or wired communication. In another embodiment ofthe invention, the system 800 is a virtualized computing system capableof executing any or all aspects of software and/or applicationcomponents presented herein on the computing devices 820, 830, 840. Incertain aspects, the computer system 800 is operable to be implementedusing hardware or a combination of software and hardware, either in adedicated computing device, or integrated into another entity, ordistributed across multiple entities or computing devices.

By way of example, and not limitation, the computing devices 820, 830,840 are intended to represent various forms of electronic devicesincluding at least a processor and a memory, such as a server, bladeserver, mainframe, mobile phone, personal digital assistant (PDA),smartphone, desktop computer, netbook computer, tablet computer,workstation, laptop, and other similar computing devices. The componentsshown here, their connections and relationships, and their functions,are meant to be exemplary only, and are not meant to limitimplementations of the invention described and/or claimed in the presentapplication.

In one embodiment, the computing device 820 includes components such asa processor 860, a system memory 862 having a random access memory (RAM)864 and a read-only memory (ROM) 866, and a system bus 868 that couplesthe memory 862 to the processor 860. In another embodiment, thecomputing device 830 is operable to additionally include components suchas a storage device 890 for storing the operating system 892 and one ormore application programs 894, a network interface unit 896, and/or aninput/output controller 898. Each of the components is operable to becoupled to each other through at least one bus 868. The input/outputcontroller 898 is operable to receive and process input from, or provideoutput to, a number of other devices 899, including, but not limited to,alphanumeric input devices, mice, electronic styluses, display units,touch screens, signal generation devices (e.g., speakers), or printers.

By way of example, and not limitation, the processor 860 is operable tobe a general-purpose microprocessor (e.g., a central processing unit(CPU)), a graphics processing unit (GPU), a microcontroller, a DigitalSignal Processor (DSP), an Application Specific Integrated Circuit(ASIC), a Field Programmable Gate Array (FPGA), a Programmable LogicDevice (PLD), a controller, a state machine, gated or transistor logic,discrete hardware components, or any other suitable entity orcombinations thereof that can perform calculations, process instructionsfor execution, and/or other manipulations of information.

In another implementation, shown as 840 in FIG. 42, multiple processors860 and/or multiple buses 868 are operable to be used, as appropriate,along with multiple memories 862 of multiple types (e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core).

Also, multiple computing devices are operable to be connected, with eachdevice providing portions of the necessary operations (e.g., a serverbank, a group of blade servers, or a multi-processor system).Alternatively, some steps or methods are operable to be performed bycircuitry that is specific to a given function.

According to various embodiments, the computer system 800 is operable tooperate in a networked environment using logical connections to localand/or remote computing devices 820, 830, 840 through a network 810. Acomputing device 830 is operable to connect to a network 810 through anetwork interface unit 896 connected to a bus 868. Computing devices areoperable to communicate communication media through wired networks,direct-wired connections or wirelessly, such as acoustic, RF, orinfrared, through an antenna 897 in communication with the networkantenna 812 and the network interface unit 896, which are operable toinclude digital signal processing circuitry when necessary. The networkinterface unit 896 is operable to provide for communications undervarious modes or protocols.

In one or more exemplary aspects, the instructions are operable to beimplemented in hardware, software, firmware, or any combinationsthereof. A computer readable medium is operable to provide volatile ornon-volatile storage for one or more sets of instructions, such asoperating systems, data structures, program modules, applications, orother data embodying any one or more of the methodologies or functionsdescribed herein. The computer readable medium is operable to includethe memory 862, the processor 860, and/or the storage media 890 and isoperable be a single medium or multiple media (e.g., a centralized ordistributed computer system) that store the one or more sets ofinstructions 900. Non-transitory computer readable media includes allcomputer readable media, with the sole exception being a transitory,propagating signal per se. The instructions 900 are further operable tobe transmitted or received over the network 810 via the networkinterface unit 896 as communication media, which is operable to includea modulated data signal such as a carrier wave or other transportmechanism and includes any delivery media. The term “modulated datasignal” means a signal that has one or more of its characteristicschanged or set in a manner as to encode information in the signal.

Storage devices 890 and memory 862 include, but are not limited to,volatile and non-volatile media such as cache, RAM, ROM, EPROM, EEPROM,FLASH memory, or other solid state memory technology; discs (e.g.,digital versatile discs (DVD), HD-DVD, BLU-RAY, compact disc (CD), orCD-ROM) or other optical storage; magnetic cassettes, magnetic tape,magnetic disk storage, floppy disks, or other magnetic storage devices;or any other medium that can be used to store the computer readableinstructions and which can be accessed by the computer system 800.

In one embodiment, the computer system 800 is within a cloud-basednetwork. In one embodiment, the server 850 is a designated physicalserver for distributed computing devices 820, 830, and 840. In oneembodiment, the server 850 is a cloud-based server platform. In oneembodiment, the cloud-based server platform hosts serverless functionsfor distributed computing devices 820, 830, and 840.

In another embodiment, the computer system 800 is within an edgecomputing network. The server 850 is an edge server, and the database870 is an edge database. The edge server 850 and the edge database 870are part of an edge computing platform. In one embodiment, the edgeserver 850 and the edge database 870 are designated to distributedcomputing devices 820, 830, and 840. In one embodiment, the edge server850 and the edge database 870 are not designated for distributedcomputing devices 820, 830, and 840. The distributed computing devices820, 830, and 840 connect to an edge server in the edge computingnetwork based on proximity, availability, latency, bandwidth, and/orother factors.

It is also contemplated that the computer system 800 is operable to notinclude all of the components shown in FIG. 42, is operable to includeother components that are not explicitly shown in FIG. 42, or isoperable to utilize an architecture completely different than that shownin FIG. 42. The various illustrative logical blocks, modules, elements,circuits, and algorithms described in connection with the embodimentsdisclosed herein are operable to be implemented as electronic hardware,computer software, or combinations of both. To clearly illustrate thisinterchangeability of hardware and software, various illustrativecomponents, blocks, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application (e.g., arranged in adifferent order or partitioned in a different way), but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

Other and further embodiments utilizing one or more aspects of theinvention described above can be devised without departing from thespirit of Applicant's invention. For example, various seals and sealconfigurations can seal the components to form the chamber in thetransducer housing assembly; various translation devices can be used tomove the transducer housing assembly along a component surface in space;various quick disconnect configurations can be used to attach the lenshousing; various ultrasonic signal generation and receive devices(combined or separate) can be used to send and/or receive signals fromthe transducer; and the like can be used to form the transducer housingassembly and the other system equipment, along with other variations canoccur in keeping within the scope of the claims.

Composite materials include materials comprising two or more materialsconnected to form one single material. Composite materials include twoor more separate materials joined by an adhesive bond layer in additionto two or more separate materials joined without adhesive. For example,composite materials include materials created by joining two or moreisotropic material, materials created by joining two or more anisotropicmaterials, or materials created by joining an isotropic material to ananisotropic material. By way of example and not of limitation, compositematerials include reinforced plastic materials, such as fiberglass,carbon fiber, or other fiber-reinforced polymers. Furthermore, by way ofexample and not of limitation, composite materials also includecomposite wood, reinforced concrete, and metal on metal compositematerials. For example, composite materials include materials comprisingtwo or more layers of aluminum.

The above-mentioned examples are provided to serve the purpose ofclarifying the aspects of the invention, and it will be apparent to oneskilled in the art that they do not serve to limit the scope of theinvention. By nature, this invention is highly adjustable, customizableand adaptable. The above-mentioned examples are just some of the manyconfigurations that the mentioned components can take on. Allmodifications and improvements have been deleted herein for the sake ofconciseness and readability but are properly within the scope of thepresent invention.

The invention claimed is:
 1. A system for non-destructive testing ofcomposite materials, comprising: an ultrasonic transducer incommunication with a processor and a display means; wherein theultrasonic transducer is operable to emit ultrasonic waves into andreceive ultrasonic waves from a test object to produce scan data;wherein the scan data comprises the entire waveform of the emittedultrasonic waves; wherein the test object includes a multiplicity ofcomponents, with at least one bond layer disposed between two adjacentcomponents; wherein the processor is operable to identify and providerelative positions of one or more gap regions in the at least one bondlayer; and wherein the processor generates and presents a graphicalrepresentation of the at least one bond layer including the one or moregap regions via the display means.
 2. The system of claim 1, wherein theultrasonic transducer operates at a frequency greater than 5 MHz.
 3. Thesystem of claim 1, wherein providing the relative positions of the oneor more gap regions includes providing at least one three-dimensional(3D) coordinate corresponding to a location of each of the one or moregap regions in the test object.
 4. The system of claim 1, wherein theprocessor is operable to identify gap regions having a width smallerthan 3 mm.
 5. The system of claim 1, wherein the processor is operableto identify gap regions having a thickness smaller than 0.5 mm.
 6. Thesystem of claim 1, wherein the processor is operable to identify gapregions, wherein two layers adjacent to the bond layer are in directcontact.
 7. The system of claim 1, wherein the ultrasonic transducer isa spherically focused ultrasonic transducer.
 8. The system of claim 1,wherein the ultrasonic transducer is disposed within a couplingfluid-filled chamber of a transducer housing assembly.
 9. A system fornon-destructive testing of composite materials, comprising: anultrasonic transducer in communication with a processor and a displaymeans; wherein the ultrasonic transducer is disposed within a couplingfluid-filled chamber of a transducer housing assembly; wherein theultrasonic transducer is operable to emit ultrasonic waves into andreceive ultrasonic waves from a test object to produce scan data;wherein the test object includes a multiplicity of components, with atleast one bond layer disposed between two adjacent components; whereinthe processor is operable to identify and provide relative positions ofone or more gap regions in the at least one bond layer; and wherein theprocessor generates and presents a graphical representation of the atleast one bond layer including the one or more gap regions via thedisplay means.
 10. The system of claim 9, wherein the processor isoperable to identify and provide relative positions of one or more gapregions in a plurality of bond layers within the test object.
 11. Thesystem of claim 9, wherein the processor is operable to identify gapregions having a width smaller than 3 mm.
 12. The system of claim 9,wherein the processor is operable to identify gap regions having athickness smaller than 0.5 mm.
 13. The system of claim 9, wherein theprocessor is operable to identify gap regions, wherein two layersadjacent to the bond layer are in direct contact.
 14. The system ofclaim 9, wherein the processor to identify and provide the relativepositions of the one or more gap regions in the at least one bond layerwithout use of a calibration block.
 15. The system of claim 9, whereinthe graphical representation of the at least one bond layer includes oneor more color coded regions corresponding to the one or more gapregions.
 16. The system of claim 9, wherein the scan data comprises theentire waveform of each of the emitted ultrasonic waves.
 17. A systemfor non-destructive testing of composite materials, comprising: anultrasonic transducer in communication with a processor and a displaymeans; wherein the ultrasonic transducer is operable to emit ultrasonicwaves into and receive ultrasonic waves from a test object to producescan data; wherein the test object includes a multiplicity ofcomponents, with at least one bond layer disposed between two adjacentcomponents; wherein the processor is operable to identify and providerelative positions of one or more gap regions in a plurality of bondlayers within the test object; and wherein the processor generates andpresents a graphical representation of the at least one bond layerincluding the one or more gap regions via the display means.
 18. Thesystem of claim 17, wherein the processor is operable to identify gapregions having a width smaller than 3 mm.
 19. The system of claim 17,wherein the processor is operable to identify gap regions having athickness smaller than 0.5 mm.
 20. The system of claim 17, wherein theultrasonic transducer is disposed within a coupling fluid-filled chamberof a transducer housing assembly.